Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0023418 (leukemia)
93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Emodin is a naturally occurring anthraquinone present in the roots and bark of numerous plants of the genus Rhamnus. Extracts from the roots, bark, and/or dried leaves of buckthorn, senna, cascara, aloe, frangula, and rhubarb have been used as laxatives since ancient times and currently are widely used in the preparation of herbal laxative preparations. Anthraquinone glycosides are poorly absorbed from the gastrointestinal tract but are cleaved by gut bacteria to produce aglycones (such as emodin) that are more readily absorbed and are responsible for the purgative properties of these preparations. There is extensive exposure to emodin and other anthraquinones resulting from the use of herb-based stimulant laxatives. Reports that 1,8-dihydroxyanthraquinone, a commonly used laxative ingredient, caused tumors in the gastrointestinal tract of rats raised the possibility of an association between colorectal cancer and the use of laxatives containing anthraquinones. Because emodin is a hydroxyanthraquinone structurally similar to 1,8-dihydroxyanthraquinone, is present in herbal laxatives, and was reported to be mutagenic in bacteria, it was considered a potential carcinogen and was selected for in-depth evaluation. Male and female F344/N rats and B6C3F1 mice were exposed to emodin (at least 94% pure) in feed for 16 days, 14 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, rat and mouse bone marrow cells, and mouse peripheral blood erythrocytes. 16-DAY STUDY IN RATS: Groups of five male and five female rats were fed diets containing 0, 600, 2,000, 5,500, 17,000, or 50,000 ppm emodin (equivalent to average daily doses of approximately 50, 170, 480, 1,400, or 3,700 mg emodin/kg body weight to males and 50, 160, 460, 1,250, or 2,000 mg/kg to females) for 15 (males) or 16 (females) days. Three female rats died before the end of the study. Mean body weights of males and females exposed to 5,500 ppm or greater were significantly less than those of the controls. Feed consumption by males and females receiving 17,000 or 50,000 ppm was decreased throughout the study. Macroscopic lesions were present in the kidney of rats exposed to 17,000 or 50,000 ppm. 16-DAY STUDY IN MICE: Groups of five male and five female mice were fed diets containing 0, 600, 2,000, 5,500, 17,000, or 50,000 ppm emodin (equivalent to average daily doses of approximately 120, 400, 1,200, or 3,800 mg/kg to males and 140, 530, 1,600, or 5,000 mg/kg to females; 50,000 ppm equivalents were not calculated due to high mortality) for 15 (males) or 16 (females) days. All mice exposed to 50,000 ppm died before the end of the study. Mice in the 17,000 ppm groups lost weight during the study. Feed consumption by 5,500 ppm females was greater than that by the controls throughout the study. Macroscopic lesions were present in the gallbladder and kidney of mice exposed to 17,000 ppm. 14-WEEK STUDY IN RATS: Groups of 10 male and 10 female rats were fed diets containing 0, 312.5, 625, 1,250, 2,500, or 5,000 ppm emodin (equivalent to average daily doses of approximately 20, 40, 80, 170, or 300 mg/kg to males and females) for 14 weeks. Mean body weights of males exposed to 2,500 ppm or greater and females exposed to 1,250 ppm or greater were significantly less than those of the controls. During the first week of the study, feed consumption by males exposed to 2,500 or 5,000 ppm and females exposed to 5,000 ppm was less than that by the controls. Feed consumption by these groups was similar to that by the controls for the remainder of the study. In rats exposed to 2,500 or 5,000 ppm, there were increases in platelet counts in males and females and segmented neutrophil counts in females. Total serum protein and albumin concentrations were decreased in females exposed to 2,500 or 5,000 ppm. Relative kidney weights of rats exposed to 1,250 ppm or greater and relative lung weights of rats exposed to 625 ppm or greater were significantly increased compared to the control groups. Relative liver weights were incree increased in females exposed to 625 ppm or greater. The estrous cycle length wassignificantly increased in females exposed to 1,250 or 5,000 ppm. All male rats exposed to 1,250 ppm or greater and all exposed female rats had pigment in the renal tubules; and the severity of pigmentation generally increased with increasing exposure concentration. The incidences of hyaline droplets in the cortical epithelial cytoplasm were increased in all groups of exposed males and in females exposed to 312.5, 625, or 1,250 ppm. 14-WEEK STUDY IN MICE: Groups of 10 male and 10 female mice were fed diets containing 0, 312.5, 625, 1,250, 2,500, or 5,000 ppm emodin (equivalent to average daily doses of approxi mately 50, 100, 190, 400, or 800 mg/kg to males and 60, 130, 240, 500, or 1,100 mg/kg to females) for 14 weeks. All mice survived to the end of the study. Mean body weights of males exposed to 2,500 or 5,000 ppm were significantly less than those of the controls. Feed consumption by exposed groups was generally similar to that by the controls. Relative kidney weights of male mice exposed to 1,250 ppm or greater, relative lung weights of males exposed to 625 ppm or greater, and relative liver weights of female mice exposed to 625 ppm or greater were increased. The incidences and severities of nephropathy were increased in males and females exposed to 1,250 ppm or greater. The incidences of renal tubule pigmentation were significantly increased in males exposed to 625 ppm or greater and in females exposed to 1,250 ppm or greater. 2-YEAR STUDY IN RATS: Groups of 65 male and 65 female rats were fed diets containing 0, 280, 830, or 2,500 ppm emodin (equivalent to average daily doses of approximately 110, 320, or 1,000 mg/kg to males and 120, 370, or 1,100 mg/kg to females) for 105 weeks. Ten male and ten female rats from each group were necropsied at 6 months. Blood samples from five male and five female rats in each group were evaluated at 3, 6, and 12 months for plasma emodin concentrations; these rats were necropsied at 12 months. Survival, Body Weights, and Feed Consumption: Survival of exposed males and females was similar to that of the controls. The mean body weights of rats in the 2,500 ppm groups were less than those of the controls beginning at week 2 of the study. Feed consumption by exposed groups was similar to that by the controls throughout the study. Pathology Findings: Three Zymbal's gland carcinomas were observed in female rats exposed to 2,500 ppm. This incidence exceeded the range observed for current historical controls and was considered an equivocal finding. At the 6- and 12-month interim evaluations and at 2 years, emodin-related increases in the incidences of renal tubule hyaline droplets occurred in all exposed groups. The incidences of renal tubule pigmentation were significantly increased in all exposed groups of males at 2 years. There were negative trends in the incidences of mononuclear cell leukemia in male and female rats, and the incidences in the 2,500 ppm groups were significantly decreased. In females exposed to 2,500 ppm, the incidence was below the historical control range; the incidence in males exposed to 2,500 ppm was at the lower end of the historical control range. 2-YEAR STUDY IN MICE: Groups of 60 male mice were fed diets containing 0, 160, 312, or 625 ppm emodin (equivalent to average daily doses of approximately 15, 35, or 70 mg/kg) for 105 weeks. Groups of 60 female mice were fed diets containing 0, 312, 625, or 1,250 ppm emodin (equivalent to average daily doses of approximately 30, 60, or 120 mg/kg) for 105 weeks. Ten male and ten female mice from each group were necropsied at 12 months. Survival, Body Weights, and Feed Consumption Survival and mean body weights of exposed males and females were similar to those of the controls. No differences in feed consumption were noted between exposed and control groups. Pathology Findings: Low incidences of renal tubule adenoma and carcinoma occurred in exposed male mice; these incidences included one carcinoma each in the 312 and 625 ppm groups. Renal tubule neoplasms are rare in male mice, and their presence in these groups suggested a possible association with emodin exposure. At the 12-month interim evaluation, the severity of nephropathy was slightly increased in males exposed to 625 ppm. Also at 12 months, the severity of nephropathy increased from minimal in the lower exposure groups to mild in females exposed to 1,250 ppm; the incidence in this group was significantly increased compared to the control group. At 2 years, the severities of nephropathy were slightly increased in males exposed to 625 ppm and females exposed to 1,250 ppm. The incidences of nephropathy were significantly increased in all exposed groups of females. At the 12-month interim evaluation, the incidences of renal tubule pigmentation were significantly increased in all exposed groups of males and in females exposed to 625 or 1,250 ppm. The severities increased with increasing exposure concentration. At 2 years, the incidences of renal tubule pigmentation were significantly increased in all exposed groups; severities increased with increasing exposure concentration. GENETIC TOXICOLOGY: Emodin was mutagenic in Salmonella typhimurium strain TA100 in the presence of S9 activation; no mutagenicity was detected in strain TA98, with or without S9. Chromosomal aberrations were induced in cultured Chinese hamster ovary cells treated with emodin, with and without S9. Three separate in vivo micronucleus tests were performed with emodin. A male rat bone marrow micronucleus test, with emodin administered by three intraperitoneal injections, gave negative results. Results of acute-exposure (intraperitoneal injection) micronucleus tests in bone marrow and peripheral blood erythrocytes of male and female mice were negative. In a peripheral blood micronucleus test on mice from the 14-week study, negative results were seen in male mice, but a weakly positive response was observed in similarly exposed females. CONCLUSIONS: Under the conditions of these 2-year feed studies, there was no evidence of carcinogenic activity of emodin in male F344/N rats exposed to 280, 830, or 2,500 ppm. There was equivocal evidence of carcinogenic activity of emodin in female F344/N rats based on a marginal increase in the incidence of Zymbal's gland carcinoma. There was equivocal evidence of carcinogenic activity of emodin in male B6C3F1 mice based on a low incidence of uncommon renal tubule neoplasms. There was no evidence of carcinogenic activity of emodin in female B6C3F1 mice exposed to 312, 625, or 1,250 ppm. Exposure of rats to emodin resulted in increased incidences of renal tubule hyaline droplets and pigmentation in males, increased incidences of renal tubule hyaline droplets in females, and increased severities of renal tubule pigmentation in males and females. Emodin exposure resulted in increased incidences of renal tubule pigmentation in male and female mice and increased incidences of nephropathy in female mice. Incidences of mononuclear cell leukemia decreased in male and female rats exposed to 2,500 ppm. Synonyms: Archin; C.I. 75440; C.I. Natural Green 2; C.I. Natural Yellow 14; emodol; frangulic acid; frangula emodin; 6-methyl- 1,3,8-trihydroxyanthraquinone; Persian Berry Lake; rheum emodin; schuttgelb; 1,3,8-trihydroxy-6-methyl-9,10- anthracenedione; 1,3,8-trihydroxy-6-methylanthraquinone; 4,5,7-trihydroxy-2-methylanthraquinone.
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PMID:NTP Toxicology and Carcinogenesis Studies of EMODIN (CAS NO. 518-82-1) Feed Studies in F344/N Rats and B6C3F1 Mice. 1256 47

Oxymetholone is a synthetic anabolic steroid used to treat a variety of conditions, including hypogonadism and delayed puberty. It is also used to correct hereditary angioneurotic edema, manage carcinoma of the breast, promote a positive nitrogen balance following injury or surgery, and stimulate erythropoiesis. Considerable amounts of androgens are consumed by athletes in attempts to improve athletic performance. The National Institute of Environmental Health Sciences and the National Cancer Institute nominated oxymetholone for study based on its extensive illicit pharmaceutical use and the limited evidence that it is a potential human carcinogen. Male and female F344/N rats received oxymetholone (greater than 99% pure) in 0.5% methylcellulose by gavage for 16 days, 14 weeks, or 2 years, and male and female B6C3F1 mice received oxymetholone in 0.5% methylcellulose by gavage for 16 days or 14 weeks. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, and mouse peripheral blood erythrocytes. 16-DAY STUDY IN RATS: Groups of five male and five female F344/N rats were administered 0, 160, 315, 625, 1,250, or 2,500 mg oxymetholone/kg body weight in 0.5% methylcellulose by gavage for 16 days. All male rats survived to the end of the study; one 2,500 mg/kg female died on day 14. The mean body weights of all dosed groups of males were significantly less than those of the vehicle controls, while those of 160 and 315 mg/kg females were significantly greater. 16-DAY STUDY IN MICE: Groups of five male and five female B6C3F1 mice were administered 0, 320, 630, 1,250, 2,500, or 5,000 mg/kg in 0.5% methylcellulose by gavage for 16 days. All mice survived to the end of the study. The final mean body weights of all dosed groups of females were greater than those of the vehicle controls. 14-WEEK STUDY IN RATS: Groups of 10 male and 10 female F344/N rats were administered 0, 80, 160, 315, 625, or 1,250 mg/kg in 0.5% methylcellulose by gavage for 14 weeks. One male rat each in the 625 and 1,250 mg/kg groups died before the end of the study. The mean body weights of males administered 160 mg/kg or greater were significantly less than those of the vehicle controls; in contrast, the mean body weights of all dosed groups of females were significantly greater. A dose-related erythrocytosis, evidenced by increases in erythrocyte counts, total hemoglobin concentrations, and hematocrit values, occurred in dosed groups of rats at week 14. A dose-related hypocholesterolemia occurred at all time points in all dosed groups of rats. Dose- and time-related decreases in 5 -nucleotidase activity occurred in treated rats. There was a transient, treatment-related increase in the activity of alanine aminotransferase in males and females. For male rats administered oxymetholone, cauda epididymis, epididymis, and testis weights and spermatid counts and total spermatid heads per testis were significantly less than those of the vehicle controls, and total spermatid heads per gram testis were significantly greater. Female rats in the 80 mg/kg group spent more time in diestrus and less time in estrus than did the vehicle controls. Kidney weights of males and females and liver and uterus weights of females were increased compared to vehicle controls in rats that received 315 mg/kg or greater; thymus weights of males and females and sartorius muscle and testis weights of males were less. Compared to the vehicle controls, rats that received 160 mg/kg or greater had increased incidences of nonneoplastic lesions of the kidney and mammary gland, and the incidences of hydrometra of the uterus and dysgenesis of the ovary were increased in dosed groups of females. Female rats administered 315 mg/kg or greater had increased incidences of cytoplasmic vacuolization of the adrenal gland and myocardial degeneration of the heart. The severities of these lesions generally increased with increasing dose. 14-WEEK STUDY IN MICE: Groups of 10 male and 10 female B6C3F1 mice were administered 0, 160, 320, 630, 1,250, or 2,500 mg/kged 0, 160, 320, 630, 1,250, or 2,500 mg/kg in 0.5% methylcellulose by gavage for 14 weeks. All mice administered oxymetholone survived until the end of the study. The mean body weights of all dosed groups were similar to those of the vehicle controls. The percentages of motile sperm in 1,250 and 2,500 mg/kg males were significantly less than those of the vehicle controls. The estrous cycle lengths of 630, 1,250, and 2,500 mg/kg females were significantly longer, and females in the 1,250 and 2,500 mg/kg groups spent more time in diestrus and less time in estrus. Kidney and liver weights of males and females were greater and thymus weights of females were less than those of the vehicle controls. All dosed females had hyperplasia of the clitoral gland, metaplasia of the parietal layer epithelium of the Bowman's capsule in the kidney, and cytoplasmic alteration of the submandibular gland; these lesions were not observed in the vehicle control group. The incidences of hypoplasia of the ovary in 320 mg/kg or greater females and of parotid gland atrophy in 1,250 and 2,500 mg/kg females were increased. The results of the 14-week oral gavage studies were generally similar in rats and mice, but rats were much more sensitive to oxymetholone. Because it was not likely that a long-term mouse study would provide significant additional toxicity information, the NTP decided to conduct a 2-year study in rats only. 2-YEAR STUDY IN RATS: Groups of 90 male F344/N rats were administered 0, 3, 30, or 150 mg/kg in 0.5% methylcellulose by gavage, and 90 female F344/N rats were administered 0, 3, 30, or 100 mg/kg in 0.5% methylcellulose by gavage for up to 104 weeks, with 9 or 10 rats per group evaluated at 3, 6, 12, or 18 months. Survival and Body Weights: Survival of all dosed groups was similar to that of the vehicle controls. The mean body weights of the 30 mg/kg male group were generally within 10% of those of the vehicle controls, but those of the 150 mg/kg group were markedly decreased. Mean body weights of 3 and 30 mg/kg females were generally greater than those of the vehicle controls throughout the study. Determinations of Oxymetholone in Plasma: The concentrations of oxymetholone in plasma of male and female rats receiving 3 mg/kg for 6, 12, or 18 months were generally below the limits of quantification; therefore, all plasma concentrations in the 3 mg/kg group are considered to be estimates (Table 8). The plasma concentrations at 30 mg/kg were approximately one order of magnitude greater than those of the estimates for males and females receiving 3 mg/kg. There were no dose-related differences in plasma concentrations in female rats receiving 30 or 100 mg/kg, but plasma concentrations in males were significantly elevated in the 150 mg/kg group. It was concluded that oxymetholone kinetics was saturated at 30 mg/kg in female but not male rats. Pathology Findings: A wide spectrum of neoplasms and nonneoplastic lesions was seen in rats administered oxymetholone for 2 years. The incidences of hepatocellular adenoma and hepatocellular adenoma or carcinoma (combined) were significantly increased in 100 mg/kg females as were the incidences of basophilic and clear cell foci in 150 mg/kg males and 100 mg/kg females compared to vehicle controls. The incidences of alveolar/bronchiolar adenoma and adenoma or carcinoma (combined) were significantly increased in 30 mg/kg females. The incidences of mineralization in the lung of 150 mg/kg males and 30 and 100 mg/kg females were significantly increased. The incidence of keratoacanthoma was increased in 30 mg/kg females, and the combined incidence of squamous cell papilloma, keratoacanthoma, basal cell adenoma, squamous cell carcinoma, or carcinoma of the sweat gland was significantly increased in 100 mg/kg females. The incidences of subcutaneous tissue fibroma and fibroma or fibrosarcoma (combined) were significantly increased in 3 mg/kg males. At 2 years, the incidences of benign pheochromocytoma and benign or malignant pheochromocytoma (combined) of the adrenal gland in 150 mg/kg males and medullary hyperplasia in 100 mg/kg females were significantly increased. The incidences of cytoplasmic vacuolization of adrenal cortical cells were significantly increased in 30 and 150 mg/kg males at 18 months and 2 years and in 100 mg/kg females beginning at 12 months and in 30 mg/kg females at 2 years. The incidences of renal tubule adenoma in 3 and 150 mg/kg males were slightly increased. An extended evaluation of the kidney was conducted, and additional incidences of renal tubule adenoma were observed in step sections in vehicle control and dosed male rats. The combined single- and step-section incidence of renal tubule adenoma was significantly increased in 3 mg/kg males. The incidences of nephropathy were significantly increased in 30 and 150 mg/kg males at 2 years and in 100 mg/kg females beginning at 3 months. The severities of nephropathy were significantly increased in dosed groups of males at 2 years and in 100 mg/kg females at 18 months and 2 years. The incidences of mineralization of the kidney were significantly increased in 150 mg/kg males at all time points. The incidences of ovarian dysgenesis were significantly increased in 100 mg/kg females beginning at 3 months and in 30 mg/kg females beginning at 6 months, and severities increased with increasing dose. The incidences of chronic myocardial degeneration (cardiomyopathy) were significantly increased in 100 mg/kg females at 6 months and 2 years and the severity was increased at 2 years. The incidences of lobular hyperplasia were increased in 150 mg/kg males at 18 months and 2 years and in 30 and 100 mg/kg females at all time points. The incidences of seminiferous tubule degeneration were significantly increased in 30 and 150 mg/kg males at 2 years, and the incidences of mineralization of the testis were increased in 150 mg/kg males at 12 months and in 30 mg/kg males at 18 months and at 2 years. Decreased incidences of neoplasms occurred in male and female rats. The incidence of uterine stromal polyp or stromal sarcoma (combined) was significantly decreased in 100 mg/kg females at 2 years. The incidences of mammary gland fibroadenoma and fibroadenoma or carcinoma (combined) were significantly decreased in all dosed groups of females. The incidences of pituitary gland pars distalis adenoma were significantly decreased in 30 and 100 mg/kg females at 2 years. The incidences of testicular interstitial cell adenoma were significantly decreased in 30 and 150 mg/kg males at 18 months and in all dosed groups at 12 months and 2 years. The incidences of mononuclear cell leukemia were significantly decreased in 30 and 150 mg/kg males and 100 mg/kg females at 2 years. GENETIC TOXICOLOGY: Oxymetholone was not mutagenic in S. typhimurium strain TA97, TA98, TA100, or TA1535, with or without S9 metabolic activation. It did not induce chromosomal aberrations in cultured Chinese hamster ovary cells, with or without S9, and no increase in the frequency of micronucleated normochromatic erythrocytes was noted in peripheral blood samples from male or female mice treated for 14 weeks with oxymetholone. CONCLUSIONS: Under the conditions of this 2-year gavage study, there was equivocal evidence of carcinogenic activity of oxymetholone in male F344/N rats based on increased incidences of subcutaneous tissue fibromas and fibromas or fibrosarcomas (combined) of the skin, variably increased incidences of benign and benign or malignant pheochromocytomas (combined) of the adrenal gland, and increased incidences of renal tubule adenomas. There was clear evidence of carcinogenic activity of oxymetholone in female F344/N rats based on increased incidences of hepatocellular neoplasms. Increased incidences of alveolar/bronchiolar neoplasms and skin neoplasms in female rats were also related to oxymetholone administration. Decreased incidences of alveolar/bronchiolar neoplasms and testicular interstitial cell adenomas in males; uterine stromal polyps or stromal sarcomas (combined), mammary gland neoplasms, and pituitary gland pars distalis adenomas in females; and mononuclear cell leukemia in males and females were related to oxymetholone administration. In addition, gavage administration of oxymetholone to male and female F344/N rats resulted in a spectrum of nonneoplastic effects frequently reported with administration of synthetic anabolic androgens. Synonyms: Adroidin; anadroyd; anasteron; anasteronal; anasterone; androstan-3-one, androstano[2,3-c]1,2,5-oxadiazol-17-ol, 17-methyl-, (5-a,17-b)-; becorel; 4,5-dihydro-2-hydroxymethylene-17-a-methyltestosterone; dynasten; HMD; 17b-hydroxy-2- (hydroxymethyl)-17-methyl-5-a-androstan-3-one; 17-hydroxy-2-(hydroxymethylene)-17-methyl-(5-a,17-b)-; 17-hydroxy- 2-(hydroxymethylene)-17-methyl-5-a-17-b-androst-3-one; 17b-hydroxy-2-(hydroxymethylene)-17-a-methyl-5-a-androstan-3-one; 17b-hydroxy-2-(hydroxymethylene)-17-methyl-5a-androstan-3-one; 17-hydroxy-2-(hydroxymethylene)-17-methyl-5-a-17- b-androstan-3-one; 17b-hydroxy-2-hydroxymethylene-17a-methyl-3-androstanone; 2-hydroxymethylene-17-a-methyl-5- a-androstan-17-b-ol-3-one; 2-hydroxymethylene-17a-methyl dihydrotestosterone; 2-hydroxymethylene-17-a-methyl-17-b- hydroxy-3-androstanone; methabol; 17a-methyl-2-hydroxymethylene-17-hydroxy-5-a-androstan-3-one; oximetholonum; oximetolona; oxitosona-50; oxymethenolone; roboral; zenalosyn Trade names: Adroyd; Anadrol; Anapolon; Anapolon 50; Nastenon; Pardroyd; Pavisoid; Plenastril; Protanabol; Synasteron
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PMID:NTP Toxicology and Carcinogenesis Studies of Oxymetholone (CAS NO. 434-07-1) in F344/N Rats and Toxicology Studies of Oxymetholone in B6C3F1 Mice (Gavage Studies). 1257 78

Pyridine is used as a denaturant in alcohol and anti freeze mixtures, as a solvent for paint, rubber, and polycarbonate resins, and as an intermediate in the manufacture of insecticides, herbicides, and fungicides. It is used in the production of piperidine, an intermediate in the manufacture of rubber and mepiquat chloride, and as an intermediate and solvent in the preparation of vitamins and drugs, dyes, textile water repellants, and flavoring agents in food. Pyridine was nominated for study because of its large production volume and its use in a variety of food, medical, and industrial products. Male and female F344/N rats, male Wistar rats, and male and female B6C3F1 mice were exposed to pyridine (approximately 99% pure) in drinking water for 13 weeks or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, L5178Y mouse lymphoma cells, cultured Chinese hamster ovary cells, Drosophila melanogaster, and mouse bone marrow cells. 13-WEEK STUDY IN F344/N RATS: Groups of 10 male and 10 female F344/N rats were exposed to pyridine in drinking water at concentrations of 0, 50, 100, 250, 500, or 1,000 ppm (equivalent to average daily doses of 5, 10, 25, 55, or 90 mg pyridine/kg body weight). Two females exposed to 1,000 ppm died during week 1. Final mean body weights of 1,000 ppm males and females and 500 ppm females were significantly less than controls. Water consumption by female rats exposed to 1,000 ppm was less than that by controls. At study termination, evidence of anemia persisted in the 500 and 1,000 ppm males and all exposed groups of females. There was evidence of hepatocellular injury and/or altered hepatic function demonstrated by increased serum alanine aminotransferase and sorbitol dehydrogenase activities and bile acid concentrations in 500 and 1,000 ppm rats. The estrous cycle length of 1,000 ppm females was significantly longer than that of the controls. Liver weights of males and females exposed to 250 ppm or greater were significantly greater than controls. In the liver, the incidences of centrilobular degeneration, hypertrophy, chronic inflammation, and pigmentation were generally increased in 500 and 1,000 ppm males and females relative to controls. In the kidney, the incidences of granular casts and hyaline degeneration (hyaline droplets) were significantly increased in 1,000 ppm males and slightly increased in 500 ppm males; these lesions are consistent with 2u-globulin nephropathy. Additionally, there were increased incidences and/or severities of protein casts, chronic inflammation, mineralization, and regeneration primarily in 500 and 1,000 ppm males. 13-WEEK STUDY IN MALE WISTAR RATS: Groups of 10 male Wistar rats were exposed to pyridine in drinking water at concentrations of 0, 50, 100, 250, 500, or 1,000 ppm (equivalent to average daily doses of 5, 10, 30, 60, or 100 mg/kg). One male rat exposed to 500 ppm died during week 1. Final mean body weights of rats exposed to 250, 500, or 1,000 ppm were significantly less than those of the controls. Water consumption by rats exposed to 1,000 ppm was lower than that by controls. There was evidence of hepatocellular injury and/or altered hepatic function in the 500 and 1,000 ppm groups, similar to that observed in the 13-week study in F344/N rats. Incidences of centrilobular degeneration, hypertrophy, chronic inflammation, and pigmentation in the liver of rats exposed to 500 or 1,000 ppm were significantly increased relative to controls. 13-WEEK STUDY IN MICE: Groups of 10 male and 10 female B6C3F1 mice were exposed to pyridine in drinking water at concentrations of 0, 50, 100, 250, 500, or 1,000 ppm (equivalent to average daily doses of 10, 20, 50, 85, or 160 mg/kg for males and 10, 20, 60, 100, or 190 mg/kg for females). One female mouse exposed to 250 ppm died during week 2. Final mean body weights of female mice exposed to 1,000 ppm were significantly less than those of controls. Water consumption by exposed female mice was lower than that by controls at week 1 but generally slightly higher than controls at week 13. Sperm motirm motility in exposed male mice was significantly decreased relative to controls. Liver weights were significantly increased relative to controls in males exposed to 100 ppm or greater and in 250 and 500 ppm females. No chemical-related lesions were observed in male or female mice. 2-YEAR STUDY IN F344/N RATS: Groups of 50 male and 50 female F344/N rats were exposed to pyridine in drinking water at concentrations of 0, 100, 200, or 400 ppm (equivalent to average daily doses of 7, 14, or 33 mg/kg) for 104 (males) or 105 (females) weeks. Survival, Body Weights, and Water Consumption Survival of exposed males and females was similar to that of controls. Mean body weights of 400 ppm males and females were generally less than those of the controls throughout the study, and those of 200 ppm males and females were less during the second year of the study. Water consumption by males and females exposed to 200 or 400 ppm was generally greater than that by controls. Pathology Findings Incidences of renal tubule adenoma and renal tubule adenoma or carcinoma (combined) in male rats exposed to 400 ppm were significantly increased compared to controls and exceeded the historical control ranges. The findings from an extended evaluation (step section) of the kidneys did not reveal additional carcinomas, but additional adenomas were observed in each group of males. In the standard evaluation, an increased incidence of renal tubule hyperplasia was observed in 400 ppm males compared to controls. Incidences of mononuclear cell leukemia in female rats were significantly increased in the 200 and 400 ppm groups, and the incidence in the 400 ppm group exceeded the historical control range. Exposure concentration-related nonneoplastic liver lesions were observed in males and females, and the incidences were generally increased in groups exposed to 400 ppm. These included centrilobular cytomegaly, cytoplasmic vacuolization, periportal fibrosis, fibrosis, centrilobular degeneration and necrosis, and pigmentation. Bile duct hyperplasia occurred more often in exposed females than in controls. 2-YEAR STUDY IN MALE WISTAR RATS: Groups of 50 male Wistar rats were exposed to pyridine in drinking water at concentrations of 0, 100, 200, or 400 ppm (equivalent to average daily doses of 8, 17, or 36 mg/kg) for 104 weeks. Survival, Body Weights, and Water Consumption Survival of rats exposed to 200 or 400 ppm was significantly less than that of the controls. Mean body weights of rats exposed to 100, 200, or 400 ppm were significantly less than controls. Water consumption was similar by control and exposed rats. Pathology Findings The incidence of testicular interstitial cell adenoma in rats exposed to 400 ppm was significantly increased compared to controls. Incidences of interstitial cell hyperplasia were observed in control and exposed groups and were slightly, but not significantly, increased in rats exposed to 200 or 400 ppm. Severity of nephropathy was marked in all groups, and additional evidence of kidney disease, including mineralization in the glandular stomach, parathyroid gland hyperplasia, and fibrous osteodystrophy, was observed in 100 and 200 ppm rats. The incidences of hepatic centrilobular degeneration and necrosis, fibrosis, periportal fibrosis, and/or pigmentation were increased in one or more exposed groups. 2-YEAR STUDY IN MICE: Groups of 50 male B6C3F1 mice were exposed to pyridine in drinking water at concentrations of 0, 250, 500, or 1,000 ppm (equivalent to average daily doses of 35, 65, or 110 mg/kg) for 104 weeks, and groups of 50 female B6C3F1 mice were exposed to pyridine in drinking water at concentrations of 0, 125, 250, or 500 ppm (equivalent to average daily doses of 15, 35, or 70 mg/kg) for 105 weeks. Survival, Body Weights, and Water Consumption Survival of exposed males and females was similar to that of the controls. Mean body weights of 250 and 500 ppm females were less than controls. Water consumption by males exposed to 250 or 500 ppm was generally greater than that by controls during the last year of the study; male mice exposed to 1,000 ppm consumed less water than controls throughout the study. Water consumption by exposed females was generally lower than that by controls during the first year of the study, but greater than controls during the second year. Pathology Findings Hepatocellular neoplasms, including hepatoblastomas, in exposed male and female mice were clearly related to pyridine exposure. Additionally, many mice had multiple hepatocellular neoplasms. The incidences of hepatocellular neoplasms in exposed males and females generally exceeded the historical control ranges for drinking water studies. Neoplasms from control mice, 1,000 ppm males, and 500 ppm females were negative when stained for p53 protein. GENETIC TOXICOLOGY: Pyridine was not mutagenic in Salmonella typhimurium strains TA98, TA100, TA1535, or TA1537 or in L5178Y mouse lymphoma cells, with or without S9 metabolic activation, and it did not induce sister chromatid exchanges or chromosomal aberrations in cultured Chinese hamster ovary cells, with or without S9. Pyridine was tested for induction of sex-linked recessive lethal mutations in adult male Drosophila melanogaster, and mixed results were obtained. In one experiment, administration by injection gave negative results, but feeding produced an equivocal response. A second experiment generated negative results by injection and feeding. A third experiment showed significant increases in sex-linked recessive lethal mutations in flies treated with pyridine by injection but not by feeding. Overall, results of the sex-linked recessive lethal mutations test in Drosophila melanogaster were considered negative by feeding and equivocal by injection. Results of a single reciprocal translocation test in male Drosophila melanogaster were negative. No induction of chromosomal aberrations or micronuclei was noted in bone marrow cells of male mice administered pyridine via intraperitoneal injection. CONCLUSIONS: Under the conditions of these 2-year drinking water studies, there was some evidence of carcinogenic activity of pyridine in male F344/N rats based on increased incidences of renal tubule neoplasms. There was equivocal evidence of carcinogenic activity of pyridine in female F344/N rats based on increased incidences of mononuclear cell leukemia. There was equivocal evidence of carcinogenic activity in male Wistar rats based on an increased incidence of interstitial cell adenoma of the testis. There was clear evidence of carcinogenic activity of pyridine in male and female B6C3F1 mice based on increased incidences of malignant hepatocellular neoplasms. In F344/N rats, exposure to pyridine resulted in increased incidences of centrilobular cytomegaly and degeneration, cytoplasmic vacuolization, and pigmentation in the liver of males and females; periportal fibrosis, fibrosis, and centrilobular necrosis in the liver of males; and bile duct hyperplasia in females. In male Wistar rats, pyridine exposure resulted in increased incidences of centrilobular degeneration and necrosis, fibrosis, periportal fibrosis, and pigmentation in the liver, and, secondary to kidney disease, mineralization in the glandular stomach and parathyroid gland hyperplasia. Synonyms: Azabenzene, azine
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PMID:NTP Toxicology and Carcinogenesis Studies of Pyridine (CAS No. 110-86-1) in F344/N Rats, Wistar Rats, and B6C3F1 Mice (Drinking Water Studies). 1257 3

Butyl benzyl phthalate is a plasticizer added to polymers to give flexibility and softness. It is used extensively in polyvinyl chloride and in cellulose plastics, polyvinyl acetate, polysulfides, and polyurethane. Butyl benzyl phthalate was nominated as part of a class study of phthalates. Previous studies of butyl benzyl phthalate by the NTP (1982a) resulted in chemical-related mortality in male rats beginning at about 14 weeks of exposure and, thus, were inadequate for evaluating carcinogenicity in male rats. The companion studies revealed a marginal increase in leukemia in female rats and no evidence of carcinogenicity in B6C3F1 mice. Consequently, the present evaluations were conducted only in F344/N rats. Male and female F344/N rats were given butyl benzyl phthalate (at least 97% pure) in feed for 10 weeks, 26 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, L5178Y mouse lymphoma cells, cultured Chinese hamster ovary cells, mouse bone marrow cells, and Drosophila melanogaster. 10-WEEK MODIFIED MATING STUDY IN RATS: Groups of 15 male F344/N rats were given 0, 300, 2,800, or 25,000 ppm butyl benzyl phthalate (equivalent to average daily doses of approximately 20, 200, or 2,200 mg butyl benzyl phthalate/kg body weight) in feed for 10 weeks. All rats survived to the end of the study. The final mean body weight and body weight gain of the 25,000 ppm group were significantly less than those of the controls. Feed consumption by the 25,000 ppm group was less than that by the controls at the end of the study. A few minimal hematology changes occurred in the 25,000 ppm male rats. There was some evidence of a minimal anemia characterized by a decreased erythrocyte count and increases in mean cell hemoglobin and platelet count. The absolute and relative prostate gland weights of the 25,000 ppm males were significantly less than those of the controls. Degeneration of the seminiferous tubule germinal epithelium was observed in all males from the 25,000 ppm group. The absolute right cauda, right epididymis, and right testis weights of the 25,000 ppm males were significantly less than those of the controls. The epididymal spermatozoal concentrations in 2,800 and 25,000 ppm males were significantly less than that in the controls. Although 10 females mated to 25,000 ppm males were initially found to be sperm positive, none of these females were pregnant at necropsy. The fertility indices of males and females in the 25,000 ppm group were significantly lower than those of the controls. The maternal body weights of females mated to 300 and 2,800 ppm males were similar to those of females mated to control males. There were no significant differences in litter data between the controls and the 300 and 2,800 ppm groups. 26-WEEK STUDY IN RATS: Groups of 15 male F344/N rats were given 0, 300, 900, 2,800, 8,300, or 25,000 ppm butyl benzyl phthalate in feed for 26 weeks. Dietary levels of 300, 900, 2,800, and 8,300 ppm delivered average daily doses of approximately 30, 60, 180, and 550 mg butyl benzyl phthalate/kg body weight. The final mean body weight and body weight gain of the 25,000 ppm males were significantly less than those of the controls. Except for the 25,000 ppm males, feed consumption by all exposed groups was similar to that by the controls. An exposure-related macrocytic responsive anemia was present in the 25,000 ppm group at all time points. Additionally, minimal erythrocyte count decreases occurred sporadically in the 2,800 and 8,300 ppm groups at various time points. Reticulocyte counts were increased on days 60 and 90. Increases in mean cell hemoglobin and mean cell hemoglobin concentrations occurred in the 8,300 and 25,000 ppm rats. The absolute right cauda, right epididymis, and right testis weights and the sperm concentration of 25,000 ppm males were significantly less than those of the controls. The incidences of hypospermia and of atrophy of the seminiferous tubule in the testis and of hypospermia in the epididymis in 25,000 ppm males were significantly greater than those in the in the controls. Degenerative changes of the testis and epididymis in the 25,000 ppm males were qualitatively and quantitatively similar to those observed in males in the 10-week modified mating study. 2-YEAR STUDY IN RATS: Groups of 60 male F344/N rats were given 0, 3,000, 6,000, or 12,000 ppm butyl benzyl phthalate (equivalent to average daily doses of approximately 120, 240, or 500 mg butyl benzyl phthalate/kg body weight), and groups of 60 female F344/N rats were given 0, 6,000, 12,000, or 24,000 ppm butyl benzyl phthalate (equivalent to average daily doses of approximately 300, 600, or 1,200 mg/kg) in feed for 2 years. Survival, Body Weights, and Feed Consumption: Survival of all exposed groups of male and female rats was similar to that of the controls. Mean body weights of the 12,000 ppm males and 24,000 ppm females were less than those of the controls throughout most of the study. Feed consumption by the females exposed to 24,000 ppm was less than that by the controls at the beginning of the study, but was similar to that by the controls by week 6. Hematology and Hormone Assays: In general, hematology changes were sporadic and minor. At 6 months, a minimal decrease in erythrocyte count and an increase in mean cell hemoglobin, similar to that which occurred in the 26-week study, occurred in male rats in the 12,000 ppm group. In female rats, a decreased hematocrit value occurred at 15 months in the 24,000 ppm group. There was also a mild decrease in triiodothyronine concentrations in the 24,000 ppm females at 6 and 15 months and at the end of the study. Pathology Findings: of pancreatic acinar cell adenoma and adenoma or carcinoma (combined) in 12,000 ppm males were significantly greater than those in the controls. The incidences of adenoma and of adenoma or carcinoma (combined) in 12,000 ppm males exceeded the ranges of historical controls from NTP 2-year feed studies. One carcinoma was observed in one 12,000 ppm male, and two adenomas were observed in 24,000 ppm females. At 2 years, the incidence of focal hyperplasia of the pancreatic acinar cell in 12,000 ppm males was significantly greater than that in the controls. At 2 years, transitional epithelial papillomas in the urinary bladder were observed in one control female and in two 24,000 ppm females. The incidence of this neoplasm exceeded the range of historical controls from NTP 2-year feed studies. The incidence of transitional epithelial hyperplasia in 24,000 ppm females was significantly greater than that in the controls. The absolute right kidney weight of 12,000 ppm females and the relative right kidney weights of all exposed groups of males and of 24,000 ppm females were significantly greater than those of the controls at the 15-month interim evaluation. The severities of renal tubule pigmentation in 12,000 ppm males and in 24,000 ppm females were greater than those in the controls at 15 months and 2 years. At 2 years, the incidences of kidney mineralization in 6,000 and 24,000 ppm females were significantly less than that in the controls, and the severity was decreased in exposed females. The incidence of preputial gland adenoma or carcinoma (combined) in 12,000 ppm male rats was significantly less than in the controls, and the incidences occurred with a negative trend. GENETIC TOXICOLOGY: Results from in vitro mutagenicity tests with butyl benzyl phthalate were uniformly negative. No mutagenic response was obtained in any of several strains of Salmonella typhimurium treated with up to 11,550 mg/plate butyl benzyl phthalate, with or without S9 metabolic activation enzymes. Negative results were also obtained in in vitro studies of mammalian cell systems with and without S9. No induction of trifluorothymidine resistance in L5178Y mouse lymphoma cells or sister chromatid exchanges and chromosomal aberrations in cultured Chinese hamster ovary cells were observed. These assays also were conducted with and without S9. No significant increase in sex-linked recessive lethal mutations was observed in germ cells of male Drosophila melanogaster after administration of butyl benzyl phthalate either in feed or by injection. In contrast to the negative results obtained in vitro and in Drosophila, butyl benzyl phthalate gave positive responses in two in vivo studies with mice. Results of a mouse bone marrow sister chromatid exchange test were positive at sample times of 23 and 42 hours, but no confirmatory test was conducted. Chromosomal aberrations were induced in bone marrow cells of male mice sampled 17 hours after intraperitoneal injection of 5,000 mg/kg butyl benzyl phthalate. CONCLUSIONS: Under the conditions of this 2-year feed study, there was some evidence of carcinogenic activity of butyl benzyl phthalate in male F344/N rats based on the increased incidences of pancreatic acinar cell adenoma and of acinar cell adenoma or carcinoma (combined). There was equivocal evidence of carcinogenic activity of butyl benzyl phthalate in female 344/N rats based on the marginally increased incidences of pancreatic acinar cell adenoma and of transitional epithelial papilloma of the urinary bladder. Exposure of rats to butyl benzyl phthalate in feed for 2 years resulted in focal hyperplasia in the pancreas in male rats and in transitional epithelial hyperplasia in the urinary bladder of female rats. Synonyms: A13-14777; BBP; 1,2-benzenedicarboxylic acid butyl phenylmethyl ester (9CI); benzyl n-butyl phthalate; n-butyl benzyl phthalate; butyl phenylmethyl 1,2-benzenedicarboxylate; NCI-C54375; phthalic acid benzyl butyl ester (8CI) Trade names: Palatinol BB; Santicizer 160; Sicol 160; Unimoll BB
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PMID:NTP Toxicology and Carcinogenesis Studies of Butyl Benzyl Phthalate (CAS No. 85-68-7) in F344/N Rats (Feed Studies). 1258 18

Tetrafluoroethylene is used in the production of polytetrafluoroethylene (Teflon(R)) and other polymers. Tetrafluoroethylene was nominated by the National Cancer Institute for toxicity and carcinogenicity studies based on the potential for human exposure to the chemical due to the large production volume and on the lack of adequate data for tetrafluoroethylene in the literature. Male and female F344/N rats and B6C3F1 mice were exposed to tetrafluoroethylene (98% to 99% pure) by whole body inhalation exposure for 16 days, 13 weeks, or 2 years. Genetic toxicity studies were conducted in mouse peripheral blood erythrocytes. 16-DAY STUDY IN RATS: Groups of five male and five female F344/N rats were exposed to 0, 312, 625, 1,250, 2,500, or 5,000 ppm tetrafluoroethylene by inhalation for 6 hours per day, 5 days per week for a total of 12 exposures during a 16-day period. All rats survived to the end of the study. The final mean body weights and body weight gains of males and females exposed to 5,000 ppm were significantly less than those of the controls. The mean body weight gain of females exposed to 2,500 ppm was also significantly less than that of the controls. There were no exposure-related clinical findings in male or female rats. There were no significant differences in hematology parameters that were considered to be related to tetrafluoroethylene exposure. Absolute and relative kidney weights of all exposed groups of males were significantly greater than those of the controls, as were those of females in the 2,500 and 5,000 ppm groups. The absolute kidney weight of females exposed to 1,250 ppm was also significantly greater than that of the controls. The relative liver weights of all exposed groups of males and the absolute liver weights of males in the 625 and 2,500 ppm groups were significantly greater than those of the controls. Increased incidences of renal tubule degeneration occurred in males and females exposed to 625 ppm or greater; this lesion was located predominantly at the corticomedullary junction. The severity of degeneration increased with increasing exposure concentration and was slightly greater in males than females. 16-DAY STUDY IN MICE: Groups of five male and five female B6C3F1 mice were exposed to 0, 312, 625, 1,250, 2,500, or 5,000 ppm tetrafluoroethylene by inhalation for 6 hours per day, 5 days per week for a total of 12 exposures during a 16-day period. All mice survived to the end of the study. Final mean body weights and body weight gains of all exposed groups of mice were similar to those of the controls. There were no exposure-related clinical findings in male or female mice. There were no significant differences in hematology parameters that were considered to be related to tetrafluoroethylene exposure. The absolute and relative liver weights of females exposed to 5,000 ppm were significantly greater than those of the controls, as was the absolute kidney weight of females in that group and the absolute liver weight of females in the 2,500 ppm group. Renal tubule karyomegaly was observed in male and female mice in the 1,250, 2,500, and 5,000 ppm groups, and the severity of this lesion increased with increasing exposure concentration. Karyomegaly was located predominantly in the inner renal cortex. 13-WEEK STUDY IN RATS: Groups of 10 male and 9 or 10 female F344/N rats were exposed to 0, 312, 625, 1,250, 2,500, or 5,000 ppm tetrafluoroethylene by inhalation for 6 hours per day, 5 days per week, for 13 weeks. All rats survived to the end of the study. The final mean body weight and body weight gain of males exposed to 5,000 ppm were significantly less than those of the controls, as was the mean body weight gain of females in this exposure group. There were no clinical findings attributed to exposure to tetrafluoroethylene. Exposure of rats to tetrafluoroethylene resulted in a concentration-dependent normocytic, normochromic, nonresponsive anemia consistent with a secondary hypoproliferative anemia. An exposure concentration-dependent proteinuria also occurred, consistent with renal tubule th renal tubule degeneration observed histopathologically. The absolute and relative liver weights of all exposed groups of males and of females in the 5,000 ppm group were significantly greater than those of the controls. The absolute and relative right kidney weights of males and females exposed to 1,250 ppm or greater and of females in the 625 ppm group were also significantly greater than those of the controls. There were no differences in sperm morphology or vaginal cytology parameters between control and exposed groups of rats. Incidences of renal tubule degeneration in males exposed to 625 ppm or greater and in females exposed to 2,500 or 5,000 ppm were significantly greater than those in the controls. Renal lesions were similar to those observed in the 16-day study and were located predominantly at the corticomedullary junction. 13-WEEK STUDY IN MICE: Groups of 10 male and 10 female B6C3F1 mice were exposed to 0, 312, 625, 1,250, 2,500, or 5,000 ppm tetrafluoroethylene by inhalation for 6 hours per day, 5 days per week, for 13 weeks. All mice survived to the end of the study. Final mean body weights and body weight gains of all exposed groups of male and female mice were generally similar to those of the controls. There were no clinical findings that were considered to be related to tetrafluoroethylene exposure. Exposure of mice to tetrafluoroethylene resulted in a concentration-dependent normocytic, normochromic, nonresponsive anemia, consistent with a secondary hypoproliferative anemia, and in polyuria. Differences in sperm morphology parameters and estrous cycle lengths were not considered to be exposure related. Incidences of karyomegaly of the renal tubule epithelial cells in male and female mice exposed to 1,250 ppm or greater were significantly greater than those in the controls. Karyomegaly was similar to that observed in the 16-day study and was observed primarily in the inner renal cortex. 2-YEAR STUDY IN RATS: Groups of 60 male rats were exposed to 156, 312, or 625 ppm and groups of 60 female rats were exposed to 312, 625, or 1,250 ppm tetrafluoroethylene by inhalation for 6 hours per day, 5 days per week, for 104 weeks, with an observation period of 11 days following the final exposure. Ten male and ten female rats from each exposure group were evaluated at 15 months for organ weights and clinical pathology. Survival, Body Weights, and Clinical Findings: Survival rates of males in the 625 ppm group and of all exposed groups of females were significantly less than those of the controls. Mean body weights of males exposed to 625 ppm were lower than those of the controls from week 81 until the end of the study, and the mean body weight of 1,250 ppm females was slightly lower than that of the controls at the end of the study. The only clinical finding associated with exposure to tetrafluoroethylene was opacity of the eyes in exposed groups of female rats; this change was observed microscopically as cataracts. Hematology, Clinical Chemistry, and Urinalysis: At the 15-month interim evaluation, there were no differences in hematology, clinical chemistry, or urinalysis parameters that were considered to be related to tetrafluoroethylene exposure. Pathology Findings: The absolute and relative kidney weights of males exposed to 625 ppm and females exposed to 1,250 ppm and the absolute kidney weight of females exposed to 625 ppm were significantly greater than those of the controls at the 15-month interim evaluation. At 15 months, renal tubule hyperplasia was observed in one male exposed to 312 ppm and one male and one female exposed to 625 ppm; oncocytic hyperplasia was observed in one female exposed to 1,250 ppm. At the end of the study, incidences of renal tubule adenoma were greater in males and females exposed to 312 ppm or greater than those in the controls. This exposure-related increase was confirmed by examination of step sections (extended evaluations). At the end of the study, the incidences of renal tubule hyperplasia in males exposed to 625 ppm and females exposed to 1,250 ppm were significantly greater than those in the controls. The incidences of renal tubule adenoma and renal tubule adenoma or carcinoma (combined) in the extended evaluations and in the standard and extended evaluations (combined) in the 1,250 ppm female group and the 625 ppm male group were significantly greater than those in the controls, and the incidences occurred with significant positive trends. Oncocytic hyperplasia was observed at the end of the study in one male exposed to 312 ppm and in three females exposed to 1,250 ppm. At 15 months and at the end of the study, the incidences of renal tubule degeneration in all exposed groups of males and in females in the 625 and 1,250 ppm groups were greater than those in the controls. Renal tubule degeneration was similar to that observed in the 13-week study and was located predominantly at the corticomedullary junction. The severity of nephropathy generally increased with increasing exposure concentration in male rats at 15 months and 2 years. The absolute and relative liver weights of females in the 1,250 ppm group and the absolute liver weight of females exposed to 625 ppm were significantly greater than those of the controls at the 15-month interim evaluation. At 2 years, the incidences of hepatocellular carcinoma and hepatocellular adenoma or carcinoma (combined) in males exposed to 312 ppm, the incidences of hepatocellular adenoma and adenoma or carcinoma (combined) in females in all exposed groups, and the incidences of hepatocellular carcinoma in females exposed to 312 or 625 ppm were significantly greater than those in the controls. Also at 2 years, the incidence of hemangiosarcoma in females exposed to 625 ppm was significantly greater than that in the controls. In all exposed groups of males, the incidences of clear cell foci at 15 months were greater than those in the controls; at 2 years, the incidences of eosinophilic foci in all exposed groups of males and the incidences of basophilic and mixed cell foci in males in the 312 and 625 ppm groups were greater than those in the controls. The incidences of mixed cell foci at 15 months in females exposed to 625 or 1,250 ppm and at 2 years in females exposed to 1,250 ppm were also significantly greater than those in the controls. At the end of the 2-year study, increased incidences of cystic degeneration occurred in the liver of all exposed groups of males, and increased incidences of hepatic angiectasis were observed in exposed groups of females. Incidences of mononuclear cell leukemia in males exposed to 156 ppm and in all exposed groups of females were significantly greater than those in the controls. Incidences of cataracts in females exposed to 1,250 ppm were greater than those in the controls at the end of the 2-year study. At the end of the study, there were slight increases in the incidences of testicular interstitial cell adenoma in rats exposed to 312 or 625 ppm. 2-YEAR STUDY IN MICE: Groups of 58 male and 58 female B6C3F1 mice were exposed to 0, 312, 625, or 1,250 ppm tetrafluoroethylene by inhalation for 6 hours per day, 5 days per week, for 95 to 96 weeks. Ten male and ten female mice from each exposure group were evaluated at 15 months for organ weights. Survival, Body Weights, and Clinical Findings: The survival rates of all exposed groups of males and females were significantly less than those of the controls. Because of the reduced survival due to exposure-related liver neoplasms, the study was terminated during week 96. Mean body weights of exposed groups of males and females were generally similar to those of the controls, except at the end of the study, when they were somewhat less than those of the controls. There were no clinical findings related to tetrafluoroethylene exposure. Pathology Findings: At the 15-month interim evaluation, there were no differences in absolute or relative kidney, liver, or lung weights between exposed and control groups of mice. At the end of the study, the incidences of multifocal coagulative necrosis of the liver were increased in males in the 625 and 1,250 ppm groups. Also at the end of the study, females in all exposed groups had greater incidences of hematopoietic cell proliferation in the liver than the controls. Angiectasis occurred in all exposed groups of males and females at 15 months and at the end of the study. At the 15-month interim evaluation, hemangiosarcomas were observed in three males exposed to 1,250 ppm and in one female exposed to 312 ppm. The incidences of hemangiosarcoma in all exposed groups of males and females at the end of the study were significantly greater than those in the controls and exceeded the historical chamber control ranges. Also at the end of the study, the incidences of hemangioma in males and females exposed to 312 ppm and in males exposed to 625 ppm were also significantly greater than those in the controls and exceeded the range in historical chamber controls. At 15 months, hepatocellular adenomas and carcinomas occurred in control males and all exposed groups of males and females. Females exposed to 625 or 1,250 ppm had significantly greater incidences of eosinophilic foci than the controls at the 15-month interim evaluation. At the end of the study, the incidences of eosinophilic foci in males exposed to 625 or 1,250 ppm and in females exposed to 312 or 625 ppm were significantly greater than those in the controls. In male and female mice, increased incidences of a variety of hepatocellular neoplasms, including adenomas, multiple adenomas, carcinomas, and multiple carcinomas, were considered related to tetrafluoroethylene exposure. At the end of the study, the incidences of histiocytic sarcoma (all organs) in all exposed groups of males and females were significantly greater than those in the controls and exceeded the historical control ranges for all organs. The greatest incidences of histiocytic sarcomas were observed in the liver and lung, but these neoplasms were also observed in the spleen, lymph nodes, bone marrow, and kidney. Significantly increased incidences of renal tubule dilatation (males) and karyomegaly (males and females), located predominantly in the inner cortex, were observed in mice exposed to 625 or 1,250 ppm at 15 months. At the end of the study, the increased incidences of dilatation and karyomegaly in all exposed groups of males and of karyomegaly in 1,250 ppm females were generally significant. Incidences of hematopoietic cell proliferation in the spleen of all exposed groups of males and females were significantly greater than those in the controls at the end of the study. Additionally, the severity of this lesion increased with increasing exposure concentration. GENETIC TOXICOLOGY: No increases in the frequency of micronucleated erythrocytes were observed in peripheral blood samples obtained from male and female mice at the end of the 13-week inhalation study of tetrafluoroethylene. CONCLUSIONS: Under the conditions of these 2-year inhalation studies, there was clear evidence of carcinogenic activity of tetrafluoroethylene in male F344/N rats based on increased incidences of renal tubule neoplasms (mainly adenomas) and hepatocellular neoplasms. There was clear evidence of carcinogenic activity of tetrafluoroethylene in female F344/N rats based on increased incidences of renal tubule neoplasms, liver hemangiosarcomas, hepatocellular neoplasms, and mononuclear cell leukemia. There was clear evidence of carcinogenic activity of tetrafluoroethylene in male and female B6C3F1 mice based on increased incidences of liver hemangiomas and hemangiosarcomas, hepatocellular neoplasms, and histiocytic sarcomas. Slight increases in the incidences of mononuclear cell leukemia and testicular interstitial cell adenomas in male rats may have been related to exposure to tetrafluoroethylene. Exposure of rats to tetrafluoroethylene resulted in increased incidences of renal tubule hyperplasia and degeneration in males and females, increased severity of kidney nephropathy in males, and increased incidences of liver angiectasis and cataracts in females. Exposure of mice to tetrafluoroethylene resulted in increased incidences of hematopoietic cell proliferation of the liver in females, liver angiectasis in males and females, renal tubule dilatation in males, renal tubule karyomegaly in males and females, and splenic hematopoietic cell proliferation in males and females. Synonyms: Perfluoroethylene; tetrafluoroethene; 1,1,2,2-tetrafluoroethylene; TFE
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PMID:NTP Toxicology and Carcinogenesis Studies of Tetrafluoroethylene (CAS No. 116-14-3) in F344 Rats and B6C3F1 Mice (Inhalation Studies). 1259 25

Isobutyl nitrite is used to a limited extent as an intermediate in the syntheses of aliphatic nitrites. It is also an ingredient of various incenses or room odorizers and is used as a euphoric. The chemical has also been used as a jet propellant and in the preparation of fuels. Isobutyl nitrite was nominated by the Consumer Product Safety Commission to the NTP for toxicology and carcinogenicity studies because of its possible contribution to the high incidence of Kaposi's sarcoma among male homosexual acquired immune deficiency syndrome patients and because of the lack of available data on the potential carcinogenicity of isobutyl nitrite. Male and female F344/N rats and B6C3F1 mice were exposed to isobutyl nitrite (purity of 93% or greater) by inhalation for 16 days, 13 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, Drosophila melanogaster, and mouse peripheral blood. 16-DAY STUDY IN RATS: Groups of five male and five female F344/N rats were exposed to 0, 100, 200, 400, 600, or 800 ppm (approximately 420, 840, 1,700, 2,500, or 3,300 mg/m(3)) isobutyl nitrite by inhalation for 6 hours per day, 5 days per week for a total of 12 exposures during a 16-day period. All males and females exposed to 600 or 800 ppm and one 400 ppm female died on the first day of the study. Final mean body weights and mean body weight gains of 400 ppm males and females were significantly lower than those of the controls. Clinical findings observed in 400 ppm males and females included ocular discharge, lethargy, hunched posture, and rough coats. Absolute and relative lung weights of all exposed groups of males and of 200 and 400 ppm females were less than those of the controls. Chemical-related hyperplasia of the bronchial epithelium was observed in 200 and 400 ppm males and females and hyperplasia of the nasal turbinate epithelium was observed in rats exposed to 400 ppm or less. Hemosiderin pigmentation was observed in the spleen of 200 and 400 ppm males and females and bone marrow hematopoietic hyperplasia was observed in rats exposed to 400 ppm or less. 16-DAY STUDY IN MICE: Groups of five male and five female B6C3F1 mice were exposed to 0, 100, 200, 400, 600, or 800 ppm (approximately 420, 840, 1,700, 2,500, or 3,300 mg/m(3)) isobutyl nitrite by inhalation for 6 hours per day, 5 days per week for a total of 12 exposures during a 16-day period. Three males and four females exposed to 800 ppm died before the end of the study. Final mean body weights and mean body weight gains of 600 and 800 ppm males and females were significantly lower than those of the controls. Mice exposed to 400 ppm or greater were lethargic and exhibited hunched posture and rough coats. Absolute and relative lung weights of 600 and 800 ppm males and the relative lung weight of 600 ppm females were significantly greater than those of the controls. Chemical-related hyperplasia of the bronchiolar epithelium was observed in all exposed groups of males and females. Lymphocytic atrophy of the spleen and thymus was observed in males and females exposed to 400 ppm or greater. 13-WEEK STUDY IN RATS: Groups of 10 male and 10 female F344/N rats were exposed to 0, 10, 25, 75, 150, or 300 ppm (approximately 42, 105, 315, 630, or 1,260 mg/m(3)) isobutyl nitrite by inhalation for 6 hours per day, 5 days per week for 13 weeks. All rats survived to the end of the study. Final mean body weights and mean body weight gains of 300 ppm males and females were significantly lower than those of the controls, as was the mean body weight gain of 150 ppm females. Clinical findings observed during the study included ruffled fur in 300 ppm males and females, hypoactivity in 300 ppm males, and hyperactivity in 150 and 300 ppm females. A very mild chemical-related methemoglobinemia and anemia occurred in male and female rats in the 75, 150, and 300 ppm groups. Hematopoietic hyperplasia occurred in the bone marrow of all exposed groups of males and females and was considered to be a secondary response to the anemia and methed methemoglobinemia. There was minimal hemosiderin pigment accumulation in the spleens of males and females exposed to 75 ppm or greater, mild to moderate epithelial cell hyperplasia of the nasal mucosa was observed in 300 ppm males and females, and minimal hyperplasia occurred in 150 ppm males and females. Hyperplasia of the bronchial epithelium was observed in 300 ppm males and females. 13-WEEK STUDY IN MICE: Groups of 10 male and 10 female B6C3F1 mice were exposed to 0, 10, 25, 75, 150, or 300 ppm (approximately 42, 105, 315, 630, or 1,260 mg/m(3)) isobutyl nitrite by inhalation for 6 hours per day, 5 days per week for 13 weeks. There were no chemical-related deaths. Final mean body weights and mean body weight gains of 150 and 300 ppm females were significantly less than those of the controls. Final mean body weights and mean body weight gains of exposed groups of males were similar to those of the controls. There were no chemical-related clinical findings. A very mild chemical-related methemoglobinemia occurred in male and female mice in the 150 and 300 ppm groups. A very mild anemia occurred in the 300 ppm groups. In the lung, increased incidences of mild to moderate hyperplasia of the bronchiolar epithelium occurred in males and females exposed to 300 ppm. Minimal hyperplasia occurred in males exposed to 75 ppm or greater and in females exposed to 150 ppm. Minimal epithelial cell hyperplasia of the nasal mucosa was observed in 300 ppm males. Increased hematopoiesis of the spleen, secondary to the hematotoxicity, occurred in males exposed to 75 ppm or greater and in females exposed to 150 or 300 ppm. Increased hemosiderosis of the spleen occurred in males exposed to 300 ppm and in females exposed to 75 ppm or greater. 2-YEAR STUDY IN RATS: Based on the low final mean body weights, anemia, and the mild to moderate nasal mucosal lesions and the hyperplastic bronchial lesions observed in 300 ppm males and females, isobutyl nitrite exposure concentrations selected for the 2-year inhalation study in rats were 37.5, 75, and 150 ppm. Groups of 56 male and 56 female rats were exposed to 0, 37.5, 75, or 150 ppm (equivalent to 0, 158, 315, or 630 mg/m(3)) isobutyl nitrite by inhalation for 6 hours per day, 5 days per week, for 103 weeks. Ten male and 10 female rats from each group were evaluated at 15 months for clinical pathology and histopathology. Survival, Body Weights, Clinical Findings, Hematology, and Clinical Chemistry: Survival rates of exposed groups of rats were greater than those of the controls, and the survival rates of 75 and 150 ppm males were significantly greater than that of the control. Mean body weights of 150 ppm males and females were 3% to 11% lower than those of the controls throughout the course of the study. There were no clinical findings considered to be related to isobutyl nitrite exposure. A very mild methemoglobinemia and anemia occurred in male and female rats exposed to 75 or 150 ppm. Pathology Findings: Incidences of alveolar/bronchiolar adenoma and alveolar/bronchiolar adenoma or carcinoma (combined) occurred with significant positive trends in exposed males and females, and the incidences of these neoplasms in 75 ppm males and in 150 ppm males and females were significantly greater than those in the controls. The incidence of alveolar/bronchiolar carcinoma was significantly greater in 150 ppm male rats than that in the controls. The incidences of alveolar epithelial hyperplasia were also increased in 75 and 150 ppm males and in all exposed groups of females. The incidences of mononuclear cell leukemia in exposed groups of males and females were significantly less than those in the controls. 2-YEAR STUDY IN MICE: Based on the low final mean body weight of 300 ppm females and the mild to moderate bronchiolar hyperplasia observed in 300 ppm males and females, isobutyl nitrite exposure concentrations selected for the 2-year inhalation study in mice were 37.5, 75, and 150 ppm. Groups of 60 male and 60 female mice were exposed to 0, 37.5, 75, or 150 ppm (equivalent to 0, 158, 315, or 630 mg/m(3)) isobutyl nitrite by inhalation for 6 hours per day, 5 days per week, for 103 weeks. As many as 10 male and 10 female mice from each group were evaluated at 15 months for clinical pathology and histopathology. Survival, Body Weights, Clinical Findings, and Hematology and Clinical Chemistry: Survival rates of exposed groups of males were similar to those of the controls. Survival rates of exposed groups of females were greater than those of the controls, and the survival rate in 37.5 ppm females was significantly greater than that of the controls. Mean body weights of exposed groups of males and of 37.5 and 75 ppm females were similar to those of the controls throughout the study. Mean body weights of 150 ppm females were lower than those of the controls from week 20 until the end of the study. There were no biologically significant clinical findings noted in the 2-year study in mice. A very mild methemoglobinemia and anemia occurred in male and female mice exposed to 75 or 150 ppm. Pathology Findings: Incidences of alveolar/bronchiolar adenoma and alveolar/bronchiolar adenoma or carcinoma (combined) occurred with significant positive trends in exposed males and females, and the incidences of these neoplasms were significantly greater than those in the controls in 75 ppm males and in 150 ppm males and females. Incidences of alveolar epithelial hyperplasia were significantly increased in 75 and 150 ppm male and female mice. Thyroid gland follicular cell adenoma occurred with a significant positive trend in male mice; the incidences of thyroid gland follicular cell hyperplasia were increased in all exposed groups of males, and the incidences in males exposed to 37.5 or 150 ppm were significantly greater than those in the controls. Incidences of serous exudate and olfactory epithelium atrophy in the nose of 150 ppm females were significantly greater than those in the controls. Incidences of minimal to mild hemosiderin pigment in the spleen of 75 and 150 ppm male mice were significantly greater than those in the controls. GENETIC TOXICOLOGY: Isobutyl nitrite was found to be mutagenic in vitro and in vivo. It induced base-pair substitution mutations in Salmonella typhimurim strains TA100 and TA1535 and sister chromatid exchanges and chromosomal aberrations in cultured Chinese hamster ovary cells. Positive responses in the S. typhimurium tests required S9 activation, but isobutyl nitrite induced chromosomal effects in cultured Chinese hamster ovary cells with and without S9. In vivo, no induction of sex-linked recessive lethal mutations was noted in the germ cells of male Drosophila melanogaster exposed to isobutyl nitrite via feeding or injection. However, significant increases in micronucleated normochromatic erythrocytes were observed in the peripheral blood of male and female mice treated with isobutyl nitrite for 90 days by inhalation. CONCLUSIONS: Under the conditions of these 2-year inhalation studies, there was clear evidence of carcinogenic activity of isobutyl nitrite in male and female F344/N rats based on the increased incidences of alveolar/bronchiolar adenoma and alveolar/bronchiolar adenoma or carcinoma (combined). There was some evidence of carcinogenic activity of isobutyl nitrite in male and female B6C3F1 mice based on the increased incidences of alveolar/bronchiolar adenoma and alveolar/bronchiolar adenoma or carcinoma (combined) in males and females. The increased incidence of thyroid gland follicular cell adenoma in male mice may have been related to isobutyl nitrite exposure. Exposure of rats and mice to isobutyl nitrite by inhalation for 2 years resulted in increased incidences of alveolar epithelial hyperplasia (male and female rats and mice), thyroid gland follicular cell hyperplasia and splenic hemosiderin pigmentation (male mice), and serous exudate and atrophy of the olfactory epithelium of the nose (female mice). Exposure of rats to isobutyl nitrite by inhalation for 2 years resulted in decreased incidences of mononuclear cell leukemia in males and females.
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PMID:NTP Toxicology and Carcinogenesis Studies of Isobutyl Nitrite (CAS No. 542-56-3) in F344 Rats and B6C3F1 Mice (Inhalation Studies). 1259 27

Scopolamine hydrobromide trihydrate is used in ophthalmic preparations and as a preanesthetic sedative. Its major use is in transdermal patches for the treatment of motion sickness. Scopolamine hydrobromide trihydrate was selected for study because of considerable human exposure resulting from its use in prescription and over-the-counter preparations. Scopolamine was a suspect carcinogen because it contains an aliphatic epoxide moiety which may act as a biological alkylating agent. Male and female F344/N rats and B6C3F1 mice received scopolamine hydrobromide trihydrate (89% pure) in distilled water by gavage for 16 days, 14 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, and mouse peripheral blood erythrocytes. 16-DAY STUDY IN RATS: Groups of five male and five female rats were administered 0, 75, 150, 300, 600, or 1,200 mg scopolamine hydrobromide trihydrate/kg body weight in distilled water by gavage for 16 days. All rats survived to the end of the study. The final mean body weights and body weight gains of males receiving 600 and 1,200 mg/kg and the mean body weight gain of males receiving 300 mg/kg were significantly lower than those of the control group. Clinical findings included bilateral pupillary dilation in all dosed animals and red eyelids in males and females receiving 1,200 mg/kg. There were no significant treatment-related gross or microscopic lesions. 16-DAY STUDY IN MICE: Groups of five male and five female mice were administered 0, 150, 250, 450, 900, or 1,800 mg scopolamine hydrobromide trihydrate/kg body weight in distilled water by gavage for 16 days. One male and two females receiving 1,800 mg/kg and one female receiving 150 mg/kg died during the study. The final mean body weights and body weight gains of dosed mice were similar to those of the control groups. Clinical findings related to scopolamine hydrobromide trihydrate administration included bilateral pupillary dilation and squinting in all dosed males and females. The relative liver weights of males receiving 1,800 mg/kg and of females in all dosed groups were significantly greater than those of the control groups. There were no significant treatment-related gross or microscopic lesions. 14-WEEK STUDY IN RATS: Groups of 10 male and 10 female rats were administered 0, 15, 45, 135, 400, or 1,200 mg scopolamine hydrobromide trihydrate/kg body weight in distilled water by gavage for 14 weeks. One female receiving 45 mg/kg, one male and one female receiving 135 mg/kg, six males and one female receiving 400 mg/kg, and eight males and seven females receiving 1,200 mg/kg died during the study. The final mean body weights and mean body weight gains of all dosed males and females were significantly lower than those of the control groups. Clinical findings included bilateral pupillary dilation in all dosed males and females and reddening of the eyes in 15 mg/kg males and 135, 400, and 1,200 mg/kg males and females. Hematocrit, hemoglobin concentration, and/or erythrocyte count in male and female rats receiving 45 mg/kg or greater were slightly higher than those of the control groups. In general, these changes were most prominent in rats in the 400 and 1,200 mg/kg groups. Higher hematocrit, hemoglobin concentration, and erythrocyte count were likely due to hemoconcentration from dehydration (relative erythrocytosis). A minimal to mild mature neutrophilia, evidenced by higher segmented neutrophil numbers than in the control group, occurred in all dosed male rats. Sperm morphology and vaginal cytology parameters in dosed rats were similar to those in the control groups. Nine male and five female dosed rats died from esophageal obstructions consisting of feed and bedding material in the posterior pharynx. Tracheal obstruction occurred concurrently with esophageal obstruction as a result of food build-up in the oropharyngeal region. This condition is considered to be secondary to the inhibitory effects of scopolamine hydrobromide trihydrate on salivary gland secretions and on esopon esophageal smooth muscle involved in swallowing. There were no other significant treatment-related gross or microscopic findings. 14-WEEK STUDY IN MICE: Groups of 10 male and 10 female mice were administered 0, 15, 45, 135, 400, or 1,200 mg scopolamine hydrobromide trihydrate/kg body weight in distilled water by gavage for 14 weeks. One male receiving 135 mg/kg and two males and one female receiving 1,200 mg/kg died during the study. The final mean body weights and mean body weight gains of all dosed male groups and females receiving 45 mg/kg and above were significantly lower than those of the control groups. Clinical observations included bilateral pupillary dilation, hyperactivity, and hypoactivity. A minimal to mild mature neutrophilia, similar to that which occurred in the 14-week rat study, occurred in male mice receiving 45 mg/kg or greater. As in the rat study, there was no microscopic evidence of inflammation that could account for the neutrophilia. The estrous cycle length of 1,200 mg/kg females was significantly greater than that in the control group. There were no significant treatment-related gross or microscopic lesions. 2-YEAR STUDY IN RATS: Groups of 60 male and 60 female rats were administered 0, 1, 5, or 25 mg scopolamine hydrobromide trihydrate/kg body weight in distilled water by gavage for 104 weeks. Ten males and ten females from each dose group, excluding the 1 mg/kg female group, were evaluated at 15 months. Survival, Body Weights, Clinical Findings, and Ophthalmic Examination Findings: The survival rates of female rats receiving 1 and 25 mg/kg were significantly lower than that of the control group. Mean body weights of 1 and 5 mg/kg males and females were similar to those of the controls throughout the study. However, mean body weights of 25 mg/kg males and females were generally lower than those of the control groups after about week 25. Clinical findings included bilateral pupillary dilation in all dosed males and females. Ophthalmic examination revealed no significant findings. Hematology: Compared to controls, hematocrit was slightly higher in the 25 mg/kg male rats, similar to the effects observed in the 14-week study; this is consistent with dehydration resulting in hemoconcentration. Reticulocyte numbers in the 25 mg/kg female rats were slightly lower than those in the controls. This result is consistent with the lower body weights, and thus a decreased nutritional status, exhibited by these animals. Plasma Scopolamine Determinations: The serum scopolamine concentrations were 6 ng scopolamine/mL serum for the 5 mg/kg female sample and 12 and 28 ng/mL for the 25 mg/kg male and female samples, respectively. The amounts of scopolamine in the other serum samples were below the minimum detection limit (4 ng/mL) of the analysis method. Neurobehavioral Findings: Horizontal motor activity of 25 mg/kg females was significantly greater than that of the control group on days 90, 180, and 360. Startle response of 5 and 25 mg/kg females was significantly lower than that of the control group on day 90. On day 180, passive avoidance of 25 mg/kg males was significantly lower than that of the control group. Pathology Findings: The incidences of adenoma of the pituitary gland pars distalis decreased with increasing dose in both male and female rats; however, this trend was only significant in males (males: vehicle control, 19/49; 1 mg/kg, 17/49; 5 mg/kg, 13/50; 25 mg/kg, 10/50; females: 20/50, 13/60, 14/50, 10/50). The incidences of adenoma of the pituitary gland pars distalis in 25 mg/kg males and all groups of dosed females were below the NTP historical control range. The incidences of hyperplasia were not significantly different from those in the control groups. The incidences of mononuclear cell leukemia in 25 mg/kg males and females were significantly lower than those of the control groups (males: 33/50, 21/50, 26/50, 24/50; females: 20/50, 6/60, 13/50, 4/50). The incidence of mononuclear cell leukemia in females receiving 25 mg/kg was well below the NTP historical range. 2-YEAR STUDY IN MICE: Groups of 70 male and 70 female mice were administered 0, 1, 5, or 25 mg scopolamine hydrobromide trihydrate/kg body weight in distilled water by gavage for 104 to 105 weeks. Ten control animals and ten animals from each dose level were evaluated at 15 months. Survival, Body Weights, Clinical Findings, and Ophthalmic Examination Findings Survival of dosed males and females was similar to that of the controls. The mean body weights of males and females receiving 1 mg/kg were similar to those of the control groups throughout the majority of the study. The mean body weights of 5 mg/kg males and females were slightly lower than those of the controls. The mean body weights of males and females receiving 25 mg/kg were lower than those of the control groups after week 13. Clinical findings included bilateral pupillary dilation in all dosed male and female groups. Ophthalmic examination revealed no significant findings. Hematology: Hematocrit, hemoglobin concentration, and erythrocyte count in 25 mg/kg female mice were slightly lower than those in the control group. These results are consistent with development of a minimal normocytic, normochromic nonresponsive anemia. The anemia may be related to the lower body weights exhibited by these animals and are presumed to be due to a decreased nutritional status. Pathology Findings: The combined incidences of hepatocellular neoplasms (adenoma or carcinoma) occurred with a significant negative trend in males and females (males: vehicle control, 30/50; 1 mg/kg, 33/50; 5 mg/kg, 14/50; 25 mg/kg, 15/50; females: 22/51, 21/50, 16/50, 9/51). The combined incidences of hepatocellular neoplasms in 5 and 25 mg/kg males were within the NTP historical control range. The incidences of clear cell foci and eosinophilic foci in dosed male groups, and eosinophilic foci in 25 mg/kg females, were significantly lower than those of the control groups. The incidences of many spontaneously occurring nonneoplastic lesions were significantly lower in dosed mice than in the control groups and usually decreased with increasing dose. These included kidney nephropathy, alveolar epithelial hyperplasia, hyperplasia of the pancreatic islets, bone marrow myelofibrosis, hyperplasia of the pituitary gland pars distalis, cystic hyperplasia of the uterus, and hematopoietic cell proliferation of the spleen. The decreased incidences of these spontaneous lesions were most likely a result of lower body weights in dosed animals. GENETIC TOXICOLOGY: Scopolamine hydrobromide trihydrate did not induce mutations in any of five strains of Salmonella typhi murium, with or without S9 metabolic activation enzymes, nor did it induce sister chromatid exchanges in cultured Chinese hamster ovary cells, with or without S9. A weakly positive response was obtained, however, in a chromosomal aberrations test conducted in cultured Chinese hamster ovary cells with very high doses of scopolamine hydrobromide trihydrate in the presence of S9; without S9, no increase in aberrations was noted. Despite the evidence for chromosomal damage observed in vitro, no increase in the frequencies of micronucleated normochromatic erythrocytes was observed in peripheral blood samples of male or female mice exposed to scopolamine hydrobromide trihydrate for 14 weeks by gavage. CONCLUSIONS: Under the conditions of these 2-year gavage studies, there was no evidence of carcinogenic activity of scopolamine hydrobromide trihydrate in male or female F344/N rats or B6C3F1 mice administered 1, 5, or 25 mg/kg. Synonyms: Scopolamine hydrobromide, 6,7-epoxytropan-3-yl, euscopol, hydroscine hydrobromide, hyoscine bromide, (-)-hyoscine hydrobromide, hysco, isoscopil, scopolammonium bromide, (s)-tropate hydrobromide trihydrate, lα-tropyl-a-scopine
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PMID:NTP Toxicology and Carcinogenesis Studies of Scopolamine Hydrobromide Trihydrate (CAS No. 6533-68-2) in F344 Rats and B6C3F1 Mice (Gavage Studies). 1259 30

p-Nitrobenzoic acid is produced in large volumes for organic synthesis and as an intermediate in the manufacture of pesticides, dyes, and industrial solvents. Groups of male and female F344/N rats and B6C3F1 mice were exposed to p-nitrobenzoic acid (>99% pure) in feed for 14 days, 13 weeks, or 2 years for toxicity and carcinogenicity studies. Genetic toxicology studies were conducted in in vitro assays with Salmonella typhimurium and cultured Chinese hamster ovary cells, and in studies of erythrocyte micronucleus formation in mice in the 13-week study. 14-DAY STUDY IN RATS: Groups of five male and five female rats were given 0, 2,500, 5,000, 10,000, 20,000, or 40,000 ppm p-nitrobenzoic acid in feed for 14 days. All rats survived until the end of the study. Male and female rats given 20,000 and 40,000 ppm lost weight. The final mean body weights of 10,000, 20,000, and 40,000 ppm males were 82%, 60%, or 52% that of the controls, and the final mean body weights of 10,000, 20,000, and 40,000 ppm females were 87%, 68%, and 65% that of the controls. There were no clinical findings that were characteristic of organ-specific toxicity. Absolute and relative spleen weights were significantly increased in rats exposed to 10,000, 20,000, and 40,000 ppm. There were decreases in erythrocyte count and hemoglobin and hematocrit values and increases in reticulocyte count, nucleated erythrocytes, and methemoglobin concentration that were most pronounced in the 20,000 and 40,000 ppm groups. Congestion of the spleen occurred in 10,000 ppm males and in 20,000 and 40,000 ppm females. Hypertrophy of the follicular epithelium of the thyroid gland was present in male and female rats exposed to 10,000, 20,000, or 40,000 ppm p-nitrobenzoic acid, while follicular hyperplasia was observed in the 40,000 ppm males and females. Atrophy of the testis was observed in 20,000 and 40,000 ppm males. Other lesions observed in 20,000 and 40,000 ppm rats included atrophy of the thymus in males and atrophy of the ovary, bone marrow, and thymus in females. 14-DAY STUDY IN MICE: Groups of five male and five female mice were given 0, 2,500, 5,000, 10,000, 20,000, or 40,000 ppm p-nitrobenzoic acid in feed for 14 days. Three males and two females given 40,000 ppm died during the study. All other animals survived until the end of the study. Male mice given 20,000 and 40,000 ppm and females given 20,000 ppm lost weight. Mean body weight gains of 20,000 and 40,000 ppm males and 10,000, 20,000, and 40,000 ppm females were significantly lower than those of the controls. There were no clinical findings related to organ-specific toxicity although lethargy and ataxia were observed in 40,000 ppm mice. Relative liver weights were significantly increased in 20,000 and 40,000 ppm males and females and in 10,000 ppm females. Absolute and relative thymus weights of 20,000 and 40,000 ppm males and of 10,000, 20,000, and 40,000 ppm females were reduced. No significant differences in hematology parameters occurred in exposed mice. Testicular degeneration was observed in three 20,000 ppm and two 40,000 ppm males. Bone marrow hemorrhage and atrophy occurred in 40,000 ppm females. 13-WEEK STUDY IN RATS: Groups of 10 male and 10 female rats were given 0, 630, 1,250, 2,500, 5,000, or 10,000 ppm pnitrobenzoic acid in feed for 13 weeks resulting in approximate daily doses of 40, 70, 160, 310, or 660 mg/kg to males and 40, 80, 170, 340, or 680 mg/kg to females. All rats survived until the end of the study. Mean body weight gains and final mean body weights were significantly less than those of the controls in 2,500, 5,000, and 10,000 ppm males and in 5,000 and 10,000 ppm females. There were no clinical findings related to organ-specific toxicity. Differences in spleen weights and hematology parameters characteristic of regenerative anemia were observed in males and females, primarily in groups given 10,000 ppm. The absolute and relative spleen weights were significantly increased in 10,000 ppm males and females and the relative spleen weights were significantly increased in 5,000 ppm males hts were significantly increased in 5,000 ppm males and females. Methemoglobin, Heinz bodies, and reticulocyte counts were increased and erythrocyte counts, hemoglobin, and hematocrit values were decreased in 10,000 ppm males and females. Congestion, pigmentation, and accumulation of macrophages in the spleen and pigmentation in the kidney occurred in 2,500, 5,000, and 10,000 ppm males. Congestion and pigmentation of the spleen occurred in 10,000 ppm females. A yellowish brown pigment (hemosiderin) in the spleen and kidney was associated with hemolytic anemia. Mild cytoplasmic hyaline droplet accumulation was present in renal tubule epithelial cells in 10,000 ppm males while karyomegaly was present in male and female rats exposed to 2,500, 5,000, and 10,000 ppm p-nitrobenzoic acid. A chemical-related testicular lesion, consisting of atrophy of the seminiferous tubules, occurred in 10,000 ppm males. 13-WEEK STUDY IN MICE: Groups of 10 male and 10 female mice were given 0, 1,250, 5,000, 10,000, or 20,000 ppm pnitrobenzoic acid in feed for 13 weeks resulting in approximate daily doses of 170, 330, 670, 1,900, or 4,000 mg/kg body weight to males and 240, 460, 970, 2,500, or 4,900 mg/kg to females. All mice survived until the end of the study, except one 1,250 ppm female that was killed accidentally. Final mean body weights and mean body weight gains of all exposed males and of 5,000, 10,000, and 20,000 ppm females were significantly lower than those of the controls. No clinical findings or differences in organ weights or histopathology related to organ-specific toxicity were observed in exposed mice. 2-YEAR STUDY IN RATS: Groups of 60 male and 60 female rats were given 0, 1,250, 2,500, or 5,000 ppm p-nitrobenzoic acid in feed for 2 years. Ten males and 10 females from each exposure group were evaluated at 15 months. Survival, Body Weights, Feed Consumption, and Clinical Findings: Two-year survival rates of 1,250 and 2,500 ppm males were similar to that of the controls. Two-year survival of 5,000 ppm males was marginally greater than that of the controls and was attributed in part to a decrease in the severity of nephropathy and a decrease in the incidence of mononuclear cell leukemia. Survival of exposed females was similar to that of the controls. Mean body weights of 5,000 ppm males were 2% to 8% lower than those of the controls through week 80. Final mean body weights of exposed males were similar to that of the controls. Mean body weights of 5,000 ppm females were 2% to 9% lower than those of the controls during the first year of the study and were 10% to 16% lower during the second year of the study. Final mean body weights of exposed females were 97% (1,250 ppm), 92% (2;500 ppm), and 84% (5,000 ppm) that of the controls. Feed consumption by exposed males and females was similar to that by the controls. Dietary levels of 1,250, 2,500, or 5,000 ppm p-nitrobenzoic acid delivered approximately 50, 100, or 210 mg/kg body weight per day to males and 60, 125, or 250 mg/kg per day to females. There were no clinical findings attributable to organ-specific toxicity. Pathology Findings: There were increases in the incidences of clitoral gland adenoma and of clitoral gland adenoma or carcinoma (combined) (4/50, 14/49, 15/49, 15/50) in exposed females. The incidences of clitoral gland adenoma or carcinoma (combined) in the exposed groups (29% to 31%) exceeded the historical control mean incidence (11%) and range (2% to 21%) in female F344/N rats in recent 2-year NTP feed studies. The increased incidences of clitoral gland neoplasms were considered to be some evidence of carcinogenic activity in female rats exposed to p-nitrobenzoic acid. The incidences of hyperplasia of the clitoral gland in exposed females were marginally lower than that of the controls (10/50, 6/49, 6/ 49, 7/50). There was a chemical-related decrease in the severity of nephropathy in male rats. Male rat kidneys were examined using both single and step-section analyses, and the incidences of renal tubule neoplasms were not statistically greater than those of the controls. Mild hyaline droplet accumulation was observed in renal tubule epithelial cells in 10,000 ppm males in the 13-week study, but this effect was not severe enough to lead to a chemical-related neoplastic response in the 2-year study as has been observed with other chemicals. At the 15-month interim evaluation, hematologic parameters characteristic of a mild regenerative anemia and significant differences in spleen weights were noted in 5,000 ppm females. These differences included decreases in erythrocyte count, hemoglobin, and hematocrit, increases in spleen weights, and hemosiderin accumulation in splenic macrophages. At 2 years, significant decreases in the incidences of mononuclear cell leukemia were observed in 5,000 ppm males and 2,500 and 5,000 ppm females (males: 29/50, 35/50, 26/50, 2/50; females: 17/50, 11/50, 3/50, 0/50). While the mechanism for this decrease is unknown, decreases in the incidence of mononuclear cell leukemia have also been observed in 2year studies with other amine/nitro compounds. 2-YEAR STUDY IN MICE: Groups of 60 male and 60 female mice were given 0, 1,250, 2,500, or 5,000 ppm p-nitrobenzoic acid in feed for 2 years. Ten males and 10 females from each exposure group were evaluated at 15 months. Survival, Body Weights, Feed Consumption, and Clinical Findings: Two-year survival rates of exposed mice were similar to those of the controls. Mean body weights of 5,000 ppm males were 6% to 12% lower than those of the controls after week 17, and mean body weights of 5,000 ppm females were 12% to 24% lower than those of the controls after week 16. The final mean body weight of 5,000 ppm females was 19% less than that of the controls; final mean body weights of males were similar to that of the controls. Feed consumption by exposed mice was similar to that by the controls. Dietary levels of 1,250, 2,500, or 5,000 ppm p-nitrobenzoic acid delivered approximately 150, 300, or 675 mg/kg per day to males and 170, 365, or 905 mg/kg per day to females. There were no clinical findings of organ-specific toxicity. No chemical-related effects on hematology parameters were noted at the 15-month interim evaluation. Pathology Findings: There were no increases or decreases in neoplasms in male or female mice that were considered to be related to chemical administration. GENETIC TOXICOLOGY: p-Nitrobenzoic acid was mutagenic in Salmonella typhimurium strain TA100 with and without S9. No mutagenic activity was noted in strains TA98, TA1535, or TA1537, with or without S9. p-Nitrobenzoic acid induced sister chromatid exchanges and chromosomal aberrations in cultured Chinese hamster ovary cells in the absence of S9; with S9, results of both tests were negative. In vivo, no increase in micronuclei was observed in peripheral blood erythrocytes of male or female mice administered p-nitrobenzoic acid in dosed feed for 13 weeks. CONCLUSIONS: Under the conditions of these 2-year feed studies, there was no evidence of carcinogenic activity of p-nitrobenzoic acid in male F344/N rats exposed to 1,250, 2,500, or 5,000 ppm. There was some evidence of carcinogenic activity of p-nitrobenzoic acid in female F344/N rats based on increases in the incidences of clitoral gland adenoma and of clitoral gland adenoma or carcinoma (combined). There was no evidence of carcinogenic activity of p-nitrobenzoic acid in male or female B6C3F1 mice exposed to 1,250, 2,500, or 5,000 ppm. There were chemical-related decreases in the incidences of mononuclear cell leukemia in exposed male and female rats. p-Nitrobenzoic acid caused mild hematologic toxicity in female rats. Synonyms: 4-Nitrobenzoic acid; nitrodracylic acid; p-nitrobenzenecarboxylic acid; p-carboxynitrobenzene
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PMID:NTP Toxicology and Carcinogenesis Studies of p-Nitrobenzoic Acid (CAS No. 62-23-7) in F344/N Rats and B6C3F1 Mice (Feed Studies). 1259 21

o-Nitroanisole is used as an intermediate for the preparation of o-anisidine and in the manufacture of azo dyes. Toxicology and carcinogenesis studies were conducted by administering o-nitroanisole (>99% pure) in the diet to groups of male and female F344 rats and B6C3F1 mice for 14 days, 13 weeks, and 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, Chinese hamster ovary cells, and mouse lymphoma cells. 14-DAY STUDIES: Groups of five male and five female F344 rats received diets containing 0, 583, 1,166, 2,332, 4,665, or 9,330 ppm o-nitroanisole. Mean body weight gains and final mean body weights of males in the 4,665 and 9,330 ppm groups were lower than those of the controls. Absolute liver weights were significantly increased in males receiving 1,166 ppm or more and in females receiving 583 ppm or more. Groups of five male and five female B6C3F1 mice received diets containing 0, 250, 500, 1,000, 2,000, or 4,000 ppm o-nitroanisole. Mean body weight gains and final mean body weights of males that received 250 ppm and females that received 4,000 ppm were significantly lower than those of the controls. No other chemical-associated effects were observed. 13-WEEK STUDIES: Groups of 10 male and 10 female F344 rats received diets containing 0, 200, 600, 2,000, 6,000, or 18,000 ppm o-nitroanisole. Final mean body weights and feed consumption by male and female rats receiving 6,000 and 18,000 ppm were lower than those of the controls. Hemoglobin and hematocrit values were significantly lower and methemoglobin levels significantly higher in males in the 6,000 and 18,000 ppm groups than in controls. Absolute liver weights were significantly increased in females that received 200, 600, 2,000, and 6,000 ppm, absolute kidney weights were significantly increased in males that received 600, 2,000, and 6,000 ppm, and absolute spleen weights were significantly increased in males and females that received 6,000 and 18,000 ppm. Groups of 10 male and 10 female B6C3F1 mice received diets containing 0, 60, 200, 600, 2,000, or 6,000 ppm o-nitroanisole. Final mean body weight gains, final mean body weights, and feed consumption by male and female mice receiving 6,000 ppm were lower than those of the controls. Hemoglobin and hematocrit values in males and females that received 2,000 or 6,000 ppm were significantly lower than those in the controls. The absolute and relative liver weights of females in the 600 ppm group and relative liver weights of males and females in the 2,000 and 6,000 ppm groups were significantly greater than those of controls. Lesions associated with exposure to o-nitroanisole were present in the urinary bladder, spleen, kidney, liver, testis, and uterus of rats. Diffuse hyperplasia of the transitional epithelium of the urinary bladder occurred in all male and female rats that received 6,000 and 18,000 ppm. A transitional cell papilloma occurred in one male and transitional cell carcinomas occurred in two males and three females receiving 18,000 ppm. Congestion of the red pulp and capsular hyperplasia of the spleen and hepatocellular hypertrophy of the liver were present in males and females from the 18,000 ppm groups. Multifocal degeneration and necrosis of the renal tubule epithelium with infiltration of mononuclear inflammatory cells were present in male rats that received 600, 2,000, and 6,000 ppm. At the 18,000 ppm level, degeneration of the seminiferous epithelium accompanied by loss of spermatogenic cells and decreased numbers of spermatozoa were observed in the testes of male rats, while uterine atrophy was observed in female rats. Hepatocyte hypertrophy of the centrilobular and midzonal regions of liver lobules was present in mice that received 200 ppm and increased in severity at higher exposure levels. 2-YEAR STUDIES: The doses selected for the 2-year study of o-nitroanisole in rats were based on lower mean body weights, reduced feed consumption, and increased severity of regenerative anemia in male and female rats receiving 6,000 and 18,000 ppm during the 13-week study. Groups of 6roups of 60 male and 60 female F344 rats received diets containing 0, 222, 666, or 2,000 ppm o-nitroanisole. Groups of 60 male and 60 female B6C3F1 mice received diets containing 0, 666, 2,000, or 6,000 ppm o-nitroanisole. After 15 months, up to 10 animals from each group were evaluated for chemical-related lesions. Survival, Body Weights, Feed Consumption, and Clinical Findings: Survival of male rats receiving 2,000 ppm was significantly lower than that of the controls due to increased severity of nephropathy. Survival of 222 and 666 ppm male rats and all exposed female rats was similar to that of the controls. Survival of groups of exposed male and female mice was similar to that of the controls. The final mean body weight of male rats receiving 2,000 ppm was lower than that of the controls. Final mean body weights of male and female mice that received 2,000 and 6,000 ppm were lower than those of the controls. Feed consumption by male and female rats was similar to that by the controls. The only clinical finding in male or female mice attributable to chemical administration was discolored urine. Neoplasms and Nonneoplastic Lesions: The incidence of mononuclear cell leukemia was significantly increased in male rats that received 666 and 2,000 ppm and in female rats that received 2,000 ppm (males: 0 ppm, 26/50; 222 ppm, 25/50; 666 ppm, 42/50; 2,000 ppm, 34/50; females: 14/50, 11/50, 14/50, 26/50). Nephropathy occurred in all male rats; the severity increased with exposure level. Focal hyperplasia of the renal tubule epithelium was present in three males receiving 222 ppm and two males receiving 2,000 ppm. Renal tubule adenomas occurred in one male from each of the 222, 666, and 2,000 ppm groups, and renal tubule carcinomas occurred in two males from the 2,000 ppm group. Focal hyperplasia of the transitional epithelium of the urinary bladder was present in one female rat that received 222 ppm and two male rats and six female rats that received 2,000 ppm. A transitional cell papilloma occurred in the urinary bladder of one female rat from the 2,000 ppm group, and a transitional cell carcinoma occurred in another female from the 2,000 ppm group. The incidence of forestomach ulcers increased in male rats that received 2,000 ppm, and the incidence of focal hyperplasia of the forestomach increased with exposure level in male and female rats. In addition, squamous cell papillomas of the forestomach were present in one female receiving 222 ppm, one male receiving 666 ppm, and one male and one female receiving 2,000 ppm, while squamous cell carcinomas were present in one male receiving 666 ppm and one male and one female receiving 2,000 ppm. The incidences of pituitary gland adenomas in male rats and mammary gland fibroadenomas in female rats decreased with exposure level. The incidence of cellular alteration in the liver was significantly increased in exposed groups of male and female mice. The incidences of hepatocellular adenoma, hepatocellular adenoma or carcinoma (combined), and hepatocellular carcinoma or hepatoblastoma (combined) were significantly increased in male mice receiving 2,000 and 6,000 ppm. The incidences of hepatocellular adenoma or carcinoma were significantly increased in female mice that received 2,000 ppm. STOP-EXPOSURE STUDY: Groups of 60 male and 60 female F344 rats received diets containing 0, 6,000, or 18,000 ppm o-nitroanisole for 27 weeks and were then maintained on control feed without further chemical exposure for up to an additional 77 weeks. Up to 10 rats from each group were evaluated for the presence of chemical-related lesions at 3, 6, 9, and 15 months. Survival and Body Weights: Survival of exposed male and female rats was significantly lower than that of the controls as a result of moribund deaths associated with significantly increased incidences of urinary bladder neoplasms, primarily transitional cell carcinomas. All male rats that received 18,000 ppm were dead by week 48 and all females that received 18,000 ppm were dead by week 61. Mean body weights of exposed male and female rats were lower than those of the controls throughout the study. Neoplasms and Nonneoplastic Lesions: Hyperplasia of the transitional epithelium of the urinary bladder was present in nearly all exposed male and female rats examined at the interim evaluations. A transitional cell carcinoma was first observed at the 3-month interim evaluation in a male rat that received 18,000 ppm. At the 6- and 9-month interim evaluations, transitional cell papillomas or carcinomas were observed in both exposed groups of male rats. Transitional cell carcinomas were observed at the 6-month interim evaluation in females receiving 18,000 ppm and at the 9-month interim evaluation in females receiving 6,000 and 18,000 ppm. Adenomatous polyps of the large intestine were observed in a small number of exposed rats at the 6-, 9-, and 15-month interim evaluations. At the end of the study, the incidence of adenomatous polyps of the large intestine was significantly increased in all exposed groups and carcinomas of the large intestine were present in four males and two females from the 18,000 ppm groups. The incidence of hyperplasia of the transitional epithelium of the kidney pelvis was significantly increased in exposed male and female rats and transitional cell papillomas were present in three males and one female that received 18,000 ppm. Transitional cell carcinomas of the kidney were present in one male receiving 6,000 ppm and six males and one female receiving 18,000 ppm. Transitional cell carcinomas of the urinary bladder were seen in nearly all exposed male and female rats. Of the males and females receiving 6,000 ppm which were without carcinomas, three males and one female had transitional cell papillomas. Generalized centrilobular hypertrophy, focal hepatocellular necrosis, multifocal hepatocellular cytoplasmic vacuolation, and Kupffer cell pigmentation were observed in the livers of male and female rats at the 3- and 6-month interim evaluations; however, only Kupffer cell pigmentation was observed at the end of the study. Congestion of the red pulp of the spleen was observed in nearly all exposed male and female rats at the 3-, 6-, and 9-month interim evaluations but the incidence was only slightly increased in the 18,000 ppm groups at the end of the study. Degeneration and atrophy of the seminiferous tubule epithelium of the testes were observed at the 3- and 6-month interim evaluations in all male rats receiving 18,000 ppm. GENETIC TOXICOLOGY: o-Nitroanisole was tested in two laboratories for mutagenicity in Salmonella typhimurium strains TA97, TA98, TA100, TA1535, and TA1537 with and without exogenous metabolic activation (S9). Positive responses were observed at both laboratories in TA100 with and without S9 activation. One laboratory found no increase in mutations, while the second laboratory detected a weakly positive response in TA1535 without S9. No mutagenic activity was observed in the other tester strains. o-Nitroanisole was positive in the mouse lymphoma assay for induction of trifluorothymidine resistance in L5178Y cells without S9 activation. In cytogenetic tests with Chinese hamster ovary cells, o-nitroanisole induced a significant increase in chromosomal aberrations at the highest dose tested in the presence of S9 activation; sister chromatid exchanges were induced both with and without S9. CONCLUSIONS: Under the conditions of these feed studies there was clear evidence of carcinogenic activity of o-nitroanisole in male and female F344 rats that received diets containing 6,000 or 18,000 ppm for 6 months based on overall increased incidences of benign and malignant neoplasms of the urinary bladder, transitional cell neoplasms of the kidney, and benign and malignant neoplasms of the large intestine. There was a chemical-related increased incidence of mononuclear cell leukemia in male and female rats receiving diets containing 222, 666, or 2,000 ppm o-nitroanisole for 2 years. Marginally increased incidences of uncommon renal tubule neoplasms in male rats and forestomach neoplasms in male and female rats were considered uncertain findings. There was clear evidence of carcinogenic activity of o-nitroanisole in male B6C3F1 mice based on increased incidences of benign and malignant hepatocellular neoplasms. There was some evidence of carcinogenic activity of o-nitroanisole in female B6C3F1 mice based on increased incidences of hepatocellular adenomas. Increased severity of nephropathy in male rats, and increased incidences of focal hyperplasia of the renal tubule epithelium and forestomach ulcers in male rats, and of transitional cell hyperplasia of the urinary bladder, focal hyperplasia of the forestomach, and hyperplasia of transitional epithelium of the kidney pelvis in male and female rats were associated with exposure to o-nitroanisole. Synonyms: Methoxynitrobenzene, nitrophenyl methyl ether
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PMID:NTP Toxicology and Carcinogenesis Studies of o-Nitroanisole (CAS No. 91-23-6) in F344 Rats and B6C3F1 Mice (Feed Studies). 1261 95

Barium chloride dihydrate, a white crystalline granule or powder, is used in pigments, aluminum refining, leather tanning and coloring, the manufacture of magnesium metal, ceramics, glass, and paper products, as a pesticide, and in medicine as a cardiac stimulant. Toxicology and carcinogenicity studies were conducted by administering barium chloride dihydrate (99% pure) in drinking water to F344/N rats and B6C3F1 mice for 15 days, 13 weeks, and 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, and mouse lymphoma cells. 15-DAY STUDY IN RATS: Groups of five males and five females received barium chloride dihydrate in the drinking water at concentrations of 0, 125, 250, 500, 1,000, or 2,000 ppm for 15 days, corresponding to average daily doses of 10, 15, 35, 60, or 110 mg barium/kg body weight to males and females. No chemical-related deaths, differences in final mean body weights, or clinical findings of toxicity were observed. Water consumption by male and female rats exposed to 2,000 ppm was slightly less (S16%) than controls during week 2. There were no significant differences in absolute or relative organ weights between exposed and control rats. No biologically significant differences in hematology, clinical chemistry, or neurobehavioral parameters occurred in rats. 15-DAY STUDY IN MICE: Groups of five males and five females received barium chloride dihydrate in the drinking water at concentrations of 0, 40, 80,173, 346, or 692 ppm for 15 days, corresponding to average daily doses of 5,10, 20, 40, or 70 mg barium/kg body weight to males and 5, 10, 15, 40, or 85 mg barium/kg body weight to females. No chemical-related deaths, differences in mean body weights or in water consumption, or clinical findings of toxicity were observed in mice. The relative liver weight of males receiving 692 ppm was significantly greater than that of the controls. The absolute and relative liver weights of females that received 692 ppm were significantly greater than those of the controls. No histopathologic evidence of toxicity was observed in mice. 13-WEEK STUDY IN RATS: Groups of 10 males and 10 females received barium chloride dihydrate in the drinking water at concentrations of 0, 125, 500, 1,000, 2,000, or 4,000 ppm for 13 weeks, corresponding to average daily doses of 10, 30, 65, 110, or 200 mg barium/kg body weight to males and 10, 35, 65, 115, or 180 mg barium/kg body weight to females. Three males and one female in the 4,000 ppm groups died during the last week of the study. The final mean body weights of male and female rats receiving 4,000 ppm were significantly lower (13% and 8%) than those of the controls. Water consumption by male and female rats in the 4,000 ppm groups was approximately 30% lower than that by the controls. No clearly chemical-related clinical findings of toxicity or neurobehavioral or cardiovascular effects were noted. Serum phosphorus levels in 2,000 and 4,000 ppm male and female rats were significantly higher than those in controls, but there were no biologically significant differences in hematology parameters or in serum sodium, potassium, or calcium levels. Renal tubule dilatation in the outer stripe of the outer medulla and cortex occurred in male and female rats receiving 4,000 ppm. 13-WEEK STUDY IN MICE: Groups of 10 males and 10 females received barium chloride dihydrate in the drinking water at concentrations of 0, 125, 500, 1,000, 2,000, or 4,000 ppm for 13 weeks, corresponding to average daily doses of 15, 55, 100, 205, or 450 mg barium/kg body weight to males and 15, 60, 110, 200, or 495 mg barium/kg body weight to females. Six males and seven females that received 4,000 ppm and one male that received 125 ppm died during the study. Final mean body weights of male and female mice receiving 4,000 ppm were significantly lower (>30%) than those of controls. Water consumption by male mice in the 4,000 ppm group was 18% lower than that by the controls; water consumption by other exposed groups of male and female mice was similar to thatd groups of male and female mice was similar to that by the controls. Clinical findings of toxicity were limited to debilitation in the surviving male and female mice receiving 4,000 ppm. The absolute and/or relative liver weights of mice receiving 1,000, 2,000, and 4,000 ppm were significantly lower than those of the controls. Multifocal to diffuse nephropathy characterized by tubule dilatation, regeneration, and atrophy occurred in 4,000 ppm male and female mice. 2-YEAR STUDY IN RATS: Groups of 60 males and 60 females received barium chloride dihydrate in the drinking water at concentrations of 0, 500, 1,250, or 2,500 ppm for 104 (males) or 105 weeks (females), corresponding to average daily doses of 15, 30, or 60 mg barium/kg body weight for males and 15, 45, or 75 mg barium/kg body weight for females. The high dose of 2,500 ppm was selected based on decreased final mean body weights, mortality, decreased water consumption, and chemical-related kidney lesions observed in the 4,000 ppm groups in the 13-week study. Survival, Body Weights, Water Consumption, and Clinical Findings: Two-year survival of exposed male and female rats was similar to that of the controls. The final mean body weights of male and female rats that received 2,500 ppm were (5% and 11%) lower than those of controls. Beginning as early as week 5, water consumption by male and female rats receiving 2,500 ppm was substantially lower than that by controls (male: 11% to 30%; female: 19% to 33%). There were no chemical-related clinical findings. Hematology and Clinical Chemistry: There were no chemical-related differences in hematology or clinical chemistry parameters in male or female rats. Special Studies: At the 15-month interim evaluation, the plasma barium concentrations (mg/ml) were significantly increased in males receiving 1,250 and 2,500 ppm and in all exposed groups of females (male: 0 ppm, 0.98; 500 ppm, 1.00; 1,250 ppm, 1.23; 2,500 ppm, 1.68; female: 0 ppm, 0.74; 500 ppm, 0.99; 1,250 ppm, 0.97; 2,500 ppm, 1.43). Barium levels in bone in rats from the 2,500 ppm groups were about 400 times greater than those in the controls. Pathology Findings: At the end of 2 years, there were no increased incidences of neoplasms or nonneoplastic lesions that could be attributed to barium chloride dihydrate. However, there were dose-related decreased incidences of adrenal medulla pheochromocytomas and mononuclear cell leukemia in male rats. 2-YEAR STUDY IN MICE: Groups of 60 males and 60 females received barium chloride dihydrate in the drinking water at concentrations of 0, 500, 1,250, or 2,500 ppm for 103 (males) or 104 weeks (females), corresponding to average daily doses of 30, 75, or 160 mg barium/kg body weight for males and 40, 90, or 200 mg barium/kg body weight for females. The high dose of 2,500 ppm was selected based on decreased final mean body weights, mortality, decreased water consumption, and chemical-related kidney lesions observed in the 4,000 ppm groups in the 13-week study. Survival, Body Weights, Water Consumption, and Clinical Findings: Two-year survival of male and female mice receiving 2,500 ppm was significantly lower than that of the controls due to renal toxicity. Final mean body weights of 2,500 ppm males and females were 9% and 12% lower than those of controls. Water consumption by male and female mice receiving barium chloride was similar to that by the controls. There were no chemical-related clinical findings. Hematology and Clinical Chemistry: There were no differences in hematology or clinical chemistry parameters measured at the 15-month interim evaluation. Special Studies: At the 15-month interim evaluation, plasma barium concentrations (mg/mL) were significantly increased in all exposed groups of mice (male: 0 ppm, 0.62; 500 ppm, 0.77; 1,250 ppm, 0.89; 2,500 ppm, 1.49; female: 0 ppm, 0.52; 500 ppm, 0.74; 1,250 ppm, 1.01; 2,500 ppm, 1.35). Pathology Findings: At the end of the 2-year study, there were increased incidences of nephropathy in male and female mice (male: 1/50, 0/50, 2/48, 19/50; female: 0/50, 2/53, 1/50, 37/54). There were no chemical-related increased incidences of neoplasms in male or female mice. The incidence of hepatocellular adenoma was significantly decreased in male mice receiving 2,500 ppm. GENETIC TOXICOLOGY: Barium chloride dihydrate was not mutagenic in Salmonella typhimurium strains TA97, TA98, TA100, TA1535, or TA1537, with or without exogenous metabolic activation (S9). It was mutagenic in L5178Y mouse lymphoma cells in the presence of S9, but it did not induce sister chromatid exchanges or chromosomal aberrations in cultured Chinese hamster ovary cells, with or without S9. CONCLUSIONS: Under the conditions of these 2-year drinking water studies, there was no evidence of carcinogenic activity of barium chloride dihydrate in male or female F344/N rats that received 500, 1,250, or 2,500 ppm. There was no evidence of carcinogenic activity of barium chloride dihydrate in male or female B6C3F1 mice that received 500, 1,250, or 2,500 ppm. There were chemical-related increased incidences of nephropathy in male and female mice.
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PMID:NTP Toxicology and Carcinogenesis Studies of Barium Chloride Dihydrate (CAS No. 10326-27-9) in F344/N Rats and B6C3F1 Mice (Drinking Water Studies). 1261 99


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