Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.2 (alanine aminotransferase)
 26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The antiandrogenic drug, flutamide (Odyne), is widely used in the treatment of carcinoma of prostate. It is well known that flutamide has adverse effects of liver disorders. To ascertain the risk of liver disorders before administering this drug, past history and lifestyle preferences were resurveyed in 123 patients who had been treated with flutamide. The results obtained were assessed in relation to the occurrence of liver disorders by multivariate logistic regression analysis. The incidence of liver disorders was 26% (33/123), with 64% of the disorders occurring within 9 months. The chi-square test for dependent variables revealed that three variables, i.e., body mass index, past history of liver disorders and elevated glutamic-pyruvic transaminase levels were significantly related to the incidence of liver disorders (p > 0.05). Multivariate analysis indicated that a history of liver disorders and elevated alanine aminotransferase (ALT) levels were related to a higher incidence of liver disorders. Elevated ALT levels were associated with a higher incidence of liver disorders and smoking was related to a lower incidence of the liver disorders.
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PMID:[Risk factor of liver disorders caused by flutamide--statistical analysis using multivariate logistic regression analysis]. 1050 Sep 55

Three hundreds of primary liver carcinoma (PLC) were subjected to hepatic resection and hepatic chemoembolization (HACE). Among them, hepatic resetion was performed in 106 cases, and HACE in 194. The two-stage operation after HACE was performed in 23 cases. Hepatitis B antigen was positive in 69.8%. PLC with cirrhosis accounted for 81.6%. The effect of hepatic resection was superior to HACE. The cause of early local recurrence after HACE can be a valuable therapy in the hepervascular PLC. However, HACE should be unsuitable for ischemic PLC. Quantitative estimation of hepatic resection of PLC with cirrhosis was dependent on 5 parameters (ALT, serum bilirubin, PT and R15TCG), and morphological changes of cirrhotic liver.
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PMID:[Hepatic resection and hepatic arterial chemoembolization for primary liver carcinoma]. 1067 26

Distal pancreatectomy with resection of the celiac axis can increase resectability of carcinoma of the body and tail of the pancreas. We performed reconstruction of the hepatic artery to avoid complications caused by a decrease in hepatic arterial flow. We carried out distal pancreatectomy with resection of the celiac axis for carcinoma of the body and tail of the pancreas in four patients. When pulsation in the proper hepatic artery was weak after occlusion of the celiac axis, we performed reconstruction of the hepatic artery, using the splenic artery, which had been taken beforehand from the resected specimen. In two patients, we performed reconstruction of the hepatic artery. These two patients underwent reconstruction of the portal vein combined with prolonged clamping of the portal vein. Levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were elevated just after the operation, but recovered to normal levels within 10 days. No complications related to hepatic ischemia were observed. These results suggested that reconstruction of the hepatic artery allowed us to safely perform distal pancreatectomy with resection of the celiac axis for carcinoma of the body and tail of the pancreas.
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PMID:Distal pancreatectomy with resection of the celiac axis and reconstruction of the hepatic artery for carcinoma of the body and tail of the pancreas. 1098 11

Based on the results of our previous pilot study, we conducted a multi-institutional phase II study of combination chemotherapy consisting of oral UFT (Taiho Pharmaceutical Co. Ltd, Tokyo) plus cisplatin (CDDP) in patients with advanced non-small cell lung cancer (NSCLC). UFT capsule containing 100 mg tegafur and 224 mg uracil was orally administered in two divided doses on days 1 through 21 making the total tegafur dose 400 mg/m(2)/day (maximum 600 mg/body). CDDP was administered by drip infusion at a dose of 20 mg/m(2) on a 5-day schedule from day 8 to 12. Treatment was repeated every 4 weeks as long as the criteria for initiation of therapy were still met. Between April 1995 and March 1997, 51 patients were entered into the study. The mean age of all 50 eligible patients was 64 years(range: 40-78). There were 21 patients with clinical stage IIIB disease and 29 patients with IV disease. Thirty-two patients had adenocarcinoma, 14 had epidermoid carcinoma, and four had large cell carcinoma. Of the 47 assessable patients, 18 achieved a partial response with an overall response rate of 38.3% (95% confidence interval: 24.4-52.2%). The median response duration was 113 days. The median survival time of the eligible patients was 12.8 months, and the 1-year survival rate was 54%. Among the 51 patients enrolled, grade 3 or 4 leukopenia developed in one patient (2%), neutropenia in six patients (11. 8%), thrombocytopenia in six patients (11. 8%), and anemia in three patients (5. 9%). Non-hematological grade 3 or 4 toxicities included anorexia in 10 patients (19.6%), nausea in ten (19.6%), vomiting in two (3.9%), and diarrhea in two (3. 9%). Grade 3 abnormal laboratory data included bilirubinemia in four (7. 8%), GPT elevation in one (2.0%), and hematuria in one (2.0%). In conclusion, combination of CDDP plus oral UFT is efficacious, with low toxicity, in the treatment of advanced NSCLC. In particular, the low hematological toxicity may warrant application of this regimen to the treatment of elderly patients and in trials of concurrent chemoradiotherapy in patients with locally advanced NSCLC.
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PMID:A phase II trial of oral UFT plus cisplatin (CDDP) in patients with non-small cell lung cancer (NSCLC). 1116 9

Objectives. To develop a prognostic-factors-based predictive model for invasive urothelial carcinoma of the urinary bladder derived from statistical comparison of clinical characteristics.Methods. The medical records for patients with invasive urinary bladder urothelial carcinoma were reviewed. Clinical data for age, sex, serum lactate dehydrogenase, creatinine, albumin, alkaline phosphatase, alanine aminotransferase, total bilirubin and hemoglobin levels, white blood cell and platelet counts, positive urine cytology, Eastern Cooperative Oncology Group performance status score, tumor size, histologic grading, T stage, presence of lymph node metastases, squamous differentiation, hydronephrosis, prostatic involvement, Charlson comorbidity index, surgical procedures, and adjuvant chemotherapy status were recorded. Univariate and multivariate analyses were performed to test independent factors for prediction of survival and disease recurrence.Results. After univariate and multivariate analyses, six independent prognostic factors were found: T stage, grading, prostatic involvement, Eastern Cooperative Oncology Group performance status score, and pretreatment serum creatinine and albumin levels. A scoring system was developed on the basis the relative risk associated with the proposed prognostic factors and patients were stratified into three groups according to their scores, with statistically significant prognostic differences revealed for each of the between-group comparisons. Independent factors affecting recurrence-free survival and best predicted disease recurrence were pretreatment serum creatinine, T stage, and surgical procedure.Conclusions. This prognostic-factors-based risk-stratification model for invasive urothelial carcinoma of the urinary bladder may help clinicians predict outcome and select the most appropriate therapeutic modalities. The incidence of recurrent disease is significantly higher for patients with poor renal function before treatment or advanced T stage and those undergoing transurethral tumor resection instead of radical cystectomy.
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PMID:Prognostic-factors-based risk-stratification model for invasive urothelial carcinoma of the urinary bladder in Taiwan. 1183 92

Indium phosphide is used to make semiconductors,injection lasers, solar cells, photodiodes, and light-emittingdiodes. Indium phosphide was nominated for study because of its widespread use in the microelectronics industry, the potential for worker exposure,and the absence of chronic toxicity data. Male and female F344/N rats and B6C3F1 mice were exposed to indium phosphide (greater than 99% pure) by inhalation for 14 weeks or 2 years. The frequency of micronuclei was determined in the peripheral blood of mice exposed to indium phosphide for 14 weeks. 14-WEEK STUDY IN RATS: Groups of 10 male and 10 female rats were exposed to particulate aerosols of indium phosphide with amass median aerodynamic diameter of approximately 1.2 microm at concentrations of 0, 1, 3, 10, 30, or 100 mg/m3 by inhalation, 6 hours per day, 5 days per week (weeks 1 through 4 and weeks 10 through 14) or 7 days per week (weeks 5 through 9) to accommodate a concurrent teratology study. One male in the 100 mg/m3 group died before the end of the study. Body weight gains of all males and females exposed to 100 mg/m3 were less than those of the chamber controls. As a result of indium phosphide exposure, the lungs of all exposed rats had a gray to black discoloration and were significantly enlarged, weighing 2.7- to 4.4-fold more than those of the chamber controls. Indium phosphide particles were observed throughout the respiratory tract and in the lung-associated lymph nodes. A spectrum of inflammatory and proliferative lesions generally occurred in the lungs of all exposed groups of rats and consisted of alveolar proteinosis, chronic inflammation, interstitial fibrosis, and alveolar epithelial hyperplasia. Pulmonary inflammation was attended by increased leukocyte and neutrophil counts in the blood. The alveolar proteinosis was the principal apparent reason for the increase in lung weights. Indium phosphide caused inflammation at the base of the epiglottis of the larynx and hyperplasia of the bronchial and mediastinal lymph nodes. Exposure to indium phosphide affected the circulating erythroid mass. It induced a microcytic erythrocytosis consistent with bone marrow hyperplasia and hematopoietic cell proliferation of the spleen. Hepatocellular necrosis was suggested by increased serum activities of alanine aminotransferase and sorbitol dehydrogenase in all exposed groups of males and in 10 mg/m3 or greater females and was confirmed microscopically in 100 mg/m3 males and females. 14-WEEK STUDY IN MICE: Groups of 10 male and 10 female mice were exposed to particulate aerosols of indium phosphide with a mass median aerodynamic diameter of approximately 1.2 microm at concentrations of 0, 1, 3, 10, 30, or 100 mg/m3 by inhalation, 6 hours per day, 5 days per week (weeks 1 through 4 and weeks 10 through 14)or 7 days per week (weeks 5 through 9). Although the effects of indium phosphide exposure were similar in rats and mice, mice were more severely affected in that all males and females in the 100 mg/m3 groups either died or were removed moribund during the study. One male and three females in the 30 mg/m3 group were also removed before the end of the study. In general, body weight gains were significantly less in males and females exposed to 3 mg/m3 or greater compared to those of the chamber controls. Mice exposed to 30 or 100 mg/m3 were lethargic and experienced rapid, shallow breathing. As in rats, lungs were discolored and enlarged 2.6- to 4.1-fold greater than those of chamber controls due to the exposure-induced alveolar proteinosis. Indium phosphide particles were observed in the nose, trachea,larynx, and lymph nodes of some exposed males and females. Alveolar proteinosis, chronic active inflammation,interstitial fibrosis, and alveolar epithelial hyperplasia were observed; these effects were more severe than in rats. Hyperplasia in the bronchial lymph nodes and squamous metaplasia, necrosis, and suppurative inflammation of the larynx were observed in some exposed males and females. Exposure to indium phosphide induced a microcytic erythrocytosis which was consistent with the observed hematopoietic cell proliferation of the spleen.2-YEAR STUDY IN RATS Groups of 60 male and 60 female rats were exposed to particulate aerosols of indium phosphide at concentrations of 0, 0.03, 0.1, or 0.3 mg/m3, 6 hours per day,5 days per week, for 22 weeks (0.1 and 0.3 mg/m3 groups) or 105 weeks (0 and 0.03 mg/m3 groups). Animals in the 0.1 and 0.3 mg/m3 group were maintained on filtered air from exposure termination at week 22 until the end of the studies. Ten males and 10 females per group were evaluated at 3 months. 3-Month Interim Evaluation: Exposure to indium phosphide for 3 months caused a microcytic erythrocytosis and also caused enlarged lungs and lesions in the respiratory tract and lung associated lymph nodes. Although qualitatively similar to those observed in the 14-week studies, these effects were considerably less severe. However, the lesions in the lungs of rats exposed to 0.1 or 0.3 mg/m3 were considered sufficiently severe that exposure was discontinued in these groups, and the groups were allowed to continue unexposed for the remainder of the study. Survival, Body Weights, and Clinical Findings: Exposure to indium phosphide had no effect on survival or body weight gain. During the last 6 months of the study, rats in the 0.03 and 0.3 mg/m3 groups became lethargic and males breathed abnormally. Pathology Findings: At 2 years, exposure to indium phosphide caused increased incidences of alveolar/bronchiolar adenomas and carcinomas in rats. Squamous cell carcinoma of the lung occurred in four male rats exposed to 0.3 mg/m3. As observed in the 14-week study and at the 3-month interim evaluation, a spectrum of inflammatory and proliferative lesions of the lung were observed in all exposed groups of males and females;however, the extent and severity of the lesions were generally greater and included atypical hyperplasia,chronic inflammation, alveolar epithelial hyperplasia and metaplasia, alveolar proteinosis, and interstitial fibrosis. Exposure to indium phosphide also caused increased incidences of benign and malignant pheochromocytomas of the adrenal gland in males and females. Marginal increases in the incidences of mononuclear cell leukemia in males and females, fibroma of the skin in males, and carcinoma of the mammary gland in females may have been related to exposure to indium phosphide. 2-YEAR STUDY IN MICE: Groups of 60 male and 60 female mice were exposed to particulate aerosols of indium phosphide at concentrations of 0, 0.03, 0.1, or 0.3 mg/m3, 6 hours per day,5 days per week, for 21 weeks (0.1 and 0.3 mg/m3 groups) or 105 weeks (0 and 0.03 mg/m3 groups). Animals in the 0.1 and 0.3 mg/m3 groups were maintained on filtered air from exposure termination at week 21 until the end of the studies. Ten males and 10 females per group were evaluated at 3 months. 3-Month Interim Evaluation:Exposure to indium phosphide for 3 months affected the circulating erythroid mass and caused enlarged lungs and lesions in the respiratory tract and lung associated lymph nodes. These effects, although qualitatively similar to those observed in the 14-week studies, were considerably less severe. However, the lesions in the lungs of mice exposed to 0.1 mg/m3 and greater were considered sufficiently severe that exposure was discontinued in these groups and the groups were allowed to continue unexposed for the remainder of the study. Survival and Body Weights: In general, exposure to indium phosphide for 2 years reduced survival and body weight gain in exposed males and females. Pathology Findings:At 2 years, exposure to indium phosphide caused increased incidences of alveolar/bronchiolar carcinomas in males and alveolar/bronchiolar adenomas and carcinomas in females. In addition to the alveolar proteinosis and chronic active inflammation seen at earlier time points, serosa fibrosis and pleural mesothelial hyperplasia were also present. The incidences of hepatocellular neoplasms were also significantly increased in exposed males and females. Exposed groups of males and females had increased incidences of eosinophilic foci of the liver at 2 years. Marginal increases in the incidences of neoplasms of the small intestines in male mice may have been related to exposure to indium phosphide. Exposure to indium phosphide also caused inflammation of the arteries of the heart, primarily the coronary arteries and the proximal aorta, and to a lesser extent the lung-associated lymph nodes in males and in females. TISSUE BURDEN ANALYSES: Deposition and clearance studies of indium following long term exposure of rats and mice to indium phosphide by inhalation were performed. Although there were quantitative differences in lung burden and kinetic parameters for rats and mice, qualitatively they were similar. Deposition of indium in the lungs appeared to follow a zero-order (constant rate) process. Retained lung burdens throughout the studies were proportional to exposure concentration and duration. No differences in elimination rates of indium from the lungs were observed as a function of exposure concentration in either rats or mice. These studies indicated that elimination of indium was quite slow. Mice exhibited clearance half-times of 144 and 163 days for the 0.1 and 0.3 mg/m3 groups, respectively, as compared to 262 and 291 days for rats exposed to the same concentrations. The lung deposition and clearance model was used to estimate the total amount of indium deposited in the lungs of rats and mice after exposure to 0.03 mg/m3 for 2 years or to 0.1 or 0.3 mg/m3 for 21 or 22 weeks, the lung burdens at the end of the 2-year study, and the area under lung burden curves (AUC). For both species, estimates at the end of 2 years indicated that the lung burdens in the continuously exposed 0.03 mg/m3 groups were greater than those in the 0.1 or 0.3 mg/m3 groups. (ABSTRACT TRUNCATED)
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PMID:Toxicology and carcinogenesis studies of indium phosphide (CAS No. 22398-90-7) in F344/N rats and B6C3F1 mice (inhalation studies). 1208 22

Quantitative determination of newly reported enzymes activity in the crude skin toxin (CST) of catfish revealed highest activities of hyaluronidase and lipase, lesser activities of phospholipase A2, lactate dehydrogenase (LDH), cholinesterase (CE), alkaline phosphatase (ALP), and aspartate transaminase (AST), and least activities of proteinase and 5-nucleotidase (5'-NT). The CST has a hemolytic activity of 54% and no ichthyotoxicity up to 500 ug/ml. The chosen dose of CST (LD12.5) showed a potential cytotoxic activity against solid Ehrlich carcinoma-bearing mice demonstrated by an increase in the mean survival time (238.8%) and tumor growth inhibition ratio (T/C) of 73%. The CST ameliorated the relative weights of heart and liver after three weeks, while modulating the elevation in the relative spleen weight throughout the treatment periods (three, six, and nine weeks). The levels of serum triglyceride, total cholesterol, and liver total lipids were normalized after three weeks, whereas the serum albumin and hepatic glycogen concentrations, as well as ALT, AST, 5'-NT, and G-6-Pase activities were ameliorated after 6 weeks. Serum levels of glucose, LDH, and creatine kinase (CK) activities were significantly modulated throughout the treatment periods. Histological examinations of the tumor and liver tissues of treated tumor-bearing animals were carried out. Tumor tissues showed many cytolytic and cytopathic changes after treatment, while liver tissues showed moderate dysplastic changes after six weeks of treatment, which became more marked after nine weeks.
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PMID:Biological activities of the crude skin toxin of the Suez Gulf oriental catfish (Plotosus lineatus) and its antitumor effect in vivo (mice). 1250 71

Methyleugenol is used as a flavoring agent in jellies, baked goods, nonalcoholic beverages, chewing gum, candy, pudding, relish, and ice cream. It is also used as a fragrance in perfumes, creams, lotions, detergents, and soaps. Methyleugenol has also been used as an insect attractant in eradication programs and as an anesthetic in rodents. Methyleugenol was nominated for testing because of its widespread use and because of its structural resemblance to safrole, a known carcinogen, and isosafrole and estragole. Male and female F344/N rats and B6C3F1 mice received methyleugenol (approximately 99% pure) in 0.5% methylcellulose by gavage for 14 weeks or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, and mouse peripheral blood erythrocytes. 14-WEEK STUDY IN RATS: Groups of 9 or 10 male and 10 female F344/N rats were administered 0, 10, 30, 100, 300, or 1,000 mg methyleugenol/kg body weight in 0.5% methylcellulose by gavage 5 days per week for 14 weeks. A water control group of 10 male and 10 female rats received deionized water by gavage. All rats survived until the end of the study. The final mean body weights of 300 and 1,000 mg/kg males and of all dosed groups of females were significantly less than those of the vehicle controls. Erythrocyte microcytosis was demonstrated by decreased mean cell volumes in 300 mg/kg males and 1,000 mg/kg males and females. There was evidence of a thrombocytosis at all time points, demonstrated by increased platelet counts in the 100 mg/kg or greater groups. The serum activities of alanine aminotransferase and sorbitol dehydrogenase were increased in the 100 mg/kg or greater rats at various time points, suggesting hepatocellular injury. Additionally, bile acid concentrations were generally increased in the 300 and 1,000 mg/kg groups at all time points, consistent with cholestasis or altered hepatic function. A hypoproteinemia and hypoalbuminemia, evidenced by decreased total protein and albumin concentrations, occurred in rats in the 300 and 1,000 mg/kg groups at all time points. Liver weights of 100, 300, and 1,000 mg/kg males and 300 and 1,000 mg/kg females and testis weights of 1,000 mg/kg males were significantly increased. Increased incidences of liver lesions occurred in 300 and 1,000 mg/kg males and females and hepatocellular adenoma occurred in one 1,000 mg/kg male. The incidences of atrophy and chronic inflammation of the mucosa of the glandular stomach were significantly increased in rats administered 300 or 1,000 mg/kg. Increased incidences of adrenal gland cortical hypertrophy and/or cytoplasmic alteration in the submandibular gland occurred in the 100 mg/kg or greater groups. 14-WEEK STUDY IN MICE: Groups of 10 male and 10 female B6C3F1 mice received methyleugenol in 0.5% methylcellulose by gavage at doses of 0, 10, 30, 100, 300, or 1,000 mg/kg, 5 days per week for 14 weeks. A water control group of 10 male and 10 female mice received deionized water by gavage. All but one male and all females receiving 1,000 mg/kg died before the end of the study. The mean body weight gains of mice in the 300 mg/kg groups were significantly less than those of the vehicle controls. The only clinical finding was toxicity manifested as generalized morbidity in mice administered 1,000 mg/kg. Liver weights of 30, 100, and 300 mg/kg males and of 300 mg/kg females were significantly increased. Male mice administered 10 or 30 mg/kg had significantly lower cauda epididymis, epididymis, and testis weights; males receiving 100 mg/kg had significantly lower spermatozoal concentrations. Increased incidences of liver lesions occurred in 1,000 mg/kg males and 300 and 1,000 mg/kg females. The incidences of lesions of the glandular stomach were increased in one or more groups administered 30 mg/kg or greater. 2-YEAR STUDY IN RATS: Groups of 50 male and 50 female rats received methyleugenol in 0.5% methylcellulose by gavage at doses of 37, 75, or 150 mg/kg, 5 days per week for 105 weeks; groups of 60 male and 60 female rats received the 0.5% me60 female rats received the 0.5% methylcellulose vehicle only. Stop-exposure groups of 60 male and 60 female rats received 300 mg/kg in 0.5% methylcellulose by gavage for 52 weeks followed by just the 0.5% methylcellulose vehicle for the remaining 53 weeks of the study. Special study groups of 10 male and 10 female rats administered 36, 75, 150, or 300 mg/kg were designated for toxicokinetic studies. Survival and Body Weights: All 150 and 300 mg/kg males died before the end of the study, and survival of 150 mg/kg females was slightly less than that of the vehicle controls. Mean body weights of all dosed groups of rats were less than those of the vehicle controls throughout most of the 2-year study. Pathology Findings: Chemical-related liver neoplasms occurred in all dosed groups of rats and included hepatocellular adenoma, hepatocellular carcinoma, hepatocholangioma, and hepatocholangiocarcinoma; at 2 years, there were positive trends in the incidences of hepatocellular adenoma, carcinoma, and adenoma or carcinoma (combined) in core study rats and in the numbers of rats with multiple liver neoplasms. Nonneoplastic lesions included eosinophilic and mixed cell foci, hepatocellular hypertrophy, oval cell hyperplasia, cystic degeneration, and bile duct hyperplasia (females); the incidences of these lesions in dosed groups of male and female rats were increased at 6 months, 12 months, and/or 2 years. Chemical-related neoplasms and nonneoplastic lesions of the glandular stomach included benign and malignant neuroendocrine tumors in the 150 and 300 mg/kg groups and females in the 75 mg/kg group. In all dosed groups of rats at all time points, the incidences of mucosal atrophy were significantly greater than in the vehicle controls. Neuroendocrine cell hyperplasia was observed in females at 6 months and males and females at 12 months and at 2 years. In core study female rats, there was a positive trend in the incidences of squamous cell papilloma or carcinoma (combined) of the forestomach, and the incidence in the 150 mg/kg group exceeded the historical control range. The incidences of renal tubule proliferative lesions in male rats were suggestive of a neoplastic effect in the kidney. Therefore, additional step sections of the kidneys of male rats were prepared. The incidences of renal tubule hyperplasia and adenoma in the extended evaluation and the combined incidences of standard and step sections in the 75, 150, and 300 mg/kg groups were greater than those in the vehicle controls. The incidences of nephropathy were increased in all dosed groups of females, and the increase was significant in the 300 mg/kg group. In dosed groups of male rats, there was a positive trend in the incidences of malignant mesothelioma, and the incidences were significantly greater in 150 and 300 mg/kg males than in the vehicle controls. The incidences of mammary gland fibroadenoma in 75 and 150 mg/kg males were significantly increased. The incidences of fibroma of the subcutaneous tissue in 37 and 75 mg/kg males and the combined incidences of fibroma or fibrosarcoma in 37, 75, and 150 mg/kg males were significantly increased. 2-YEAR STUDY IN MICE: Groups of 50 male and 50 female mice received methyleugenol in 0.5% methylcellulose by gavage at doses of 0, 37, 75, or 150 mg/kg for 105 weeks. Special study groups of 10 male and 10 female mice administered 37, 75, or 150 mg/kg were designated for toxicokinetic studies. Survival and Body Weights: Survival of all dosed groups of male mice was similar to that of the vehicle controls. Survival of dosed groups of females was significantly less. Mean body weights of dosed mice were generally less than those of the vehicle controls throughout the studies. Pathology Findings: Chemical-related increases in the incidences of liver neoplasms and nonneoplastic lesions in mice included hepatocellular adenoma and carcinoma, hepatoblastoma, hepatocholangiocarcinoma, eosinophilic foci, oval cell hyperplasia, bile duct hyperplasia, hemosiderin pigmentation, chronic active inflammation, and hematopoietic cell proliferation. In all dosed groups ofmales and females, the incidences of hepatocellular neoplasms and the multiplicity of neoplasms were generally greater than in the vehicle controls. The incidences of hepatoblastoma were significantly increased in all dosed groups of females and slightly increased in 150 mg/kg males. Hepatocholangiocarcinoma was observed in 150 mg/kg females. The incidences of eosinophilic foci, oval cell hyperplasia, portal hypertrophy, hepatocyte necrosis, hematopoietic cell proliferation, bile duct hyperplasia, and hemosiderin pigmentation were significantly increased in two or more dosed groups of male and/or female mice. The incidences of glandular ectasia, mucosal atrophy, chronic active inflammation, epithelial hyperplasia, and neuroendocrine cell hyperplasia of the glandular stomach were increased in one or more dosed groups of male and female mice. In addition, malignant neuroendocrine tumors were observed in the glandular stomach of two 150 mg/kg male mice; one male in this group had a carcinoma. TOXICOKINETIC STUDIES: Methyleugenol is rapidly absorbed following oral administration to rats and mice. The kinetic data are consistent with rapid clearance from the blood, metabolism in the liver, and excretion of the parent and various metabolites in the urine. GENETIC TOXICOLOGY: Methyleugenol was not mutagenic in S. typhimurium strain TA98, TA100, TA1535, or TA1537, with or without exogenous metabolic activation (S9). In cytogenetic tests with cultured Chinese hamster ovary cells, methyleugenol induced sister chromatid exchanges in the presence of S9, but no induction of chromosomal aberrations was noted in cultured Chinese hamster ovary cells following exposure to methyleugenol, with or without S9. In vivo, no increase in the frequency of micronucleated normochromatic erythrocytes was seen in male or female mice administered methyleugenol by gavage for 14 weeks. PHYSIOLOGICALLY BASED PHARMACOKINETIC MODEL: A physiologically based pharmacokinetic (PBPK) model resulting from intravenous and oral exposure was created to characterize tissue concentrations of methyleugenol in rats and mice. Data used to create the model were obtained from the literature or from current studies. The primary conclusions that can be reached from the PBPK model are: 1) absorption of oral doses of methyleugenol in rats and mice is rapid and complete, 2) distribution of methyleugenol to tissues is not hampered by capillary permeability, and 3) metabolism of methyleugenol is saturable and must have some extrahepatic component in the mouse. Model-based plasma methyleugenol concentrations were not found to be good dosimeters for evaluating neoplasm dose-response data. CONCLUSIONS: Under the conditions of these 2-year gavage studies, there was clear evidence of carcinogenic activity of methyleugenol in male and female F344/N rats based on the increased incidences of liver neoplasms and neuroendocrine tumors of the glandular stomach in male and female rats and the increased incidences of kidney neoplasms, malignant mesothelioma, mammary gland fibroadenoma, and subcutaneous fibroma and fibroma or fibrosarcoma (combined) in male rats. A marginal increase in the incidence of squamous cell neoplasms of the forestomach may have been related to methyleugenol administration in female rats. There was clear evidence of carcinogenic activity of methyleugenol in male and female B6C3F1 mice based on the increased incidences of liver neoplasms. Neuroendocrine tumors of the glandular stomach in male mice were also considered related to methyleugenol administration. In male and female rats and mice, methyleugenol administration caused significant increases in nonneoplastic lesions of the liver and glandular stomach. Synonyms: 1-Allyl-1,2-dimethoxybenzene; 4-allylveratrole; 4-allyl-1,2-dimethoxy-benzene; 1,2-dimethoxy-4-allylbenzene; 3,4-dimethoxyallylbenzene; ENT 21040; 1-(3,4-dimethoxyphenyl)-2-propene; eugenol methyl ether; 1,3,4-eugenol methyl ether; veratrole methyl ether.
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PMID:NTP Toxicology and Carcinogenesis Studies of Methyleugenol (CAS NO. 93-15-2) in F344/N Rats and B6C3F1 Mice (Gavage Studies). 1256 49

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


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