Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019209 (hepatomegaly)
 5,798 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of long-term administration of nafenopin, a potent hypolipidemic drug with marked hepatomegalic and peroxisome-proliferative properties, were studied in wild-type (Csa strain) and acatalasemic (Csb strain) mice. Nafenopin was administered in the diet at a concentration of 0.1% during the first 12 months and then at 0.05% until the termination of the experiment at 20 months. By 56 weeks, 100% mortality occurred in both male and female wild-type mice, whereas the mortality rate in acatalasemic mice was approximately 50%. Between 18 and 20 months of the experiment, 9 of 9 male and 12 of 12 female acatalasemic mice that survived chronic nafenopin treatment developed hepatocellular carcinomas, some of which metastasized to the lungs. None of the 15 male and 15 female acatalasemic controls developed liver cancers. Numerous peroxisomes were seen in the lung metastases of these hepatocellular carcinomas on electron microscopic examination; in contrast the number of peroxisomes in primary liver tumor cells varied considerably. The hepatocarcinogenicity of nafenopin strongly suggests the need for long-term studies with other hypolipidemic drugs that cause hepatomegaly and peroxisome proliferation to clarify the role, if any, of peroxisome proliferation in liver carcinogenesis.
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PMID:Hepatocellular carcinomas in acatalasemic mice treated with nafenopin, a hypolipidemic peroxisome proliferator. 17 2

Liver enlargement is frequently reported in studies on the short-term toxicity of chemicals. In many such studies no histological evidence of damage is present but biochemically there is often an increased microsomal enzyme activity (MEA) which is interpreted to represent a type of work hypertrophy. In a few instances, the MEA in the enlarged liver is either normal or less than normal. In such instances histochemical evidence of liver damage (depression of G-6-Pase and autophagy) is found. A compound which produced the latter changes is Ponceau MX. When administered for up to 21 months at a dose-level which produces biochemical and histochemical evidence of liver injury, a series of changes were observed consisting of progerssive diminution of MEA, areas of glycogen accumulation and centrilobular fatty change and these were followed first by nodular hyperplasia and then by frank carcinoma. The protective effect of increased MEA in carcinogenesis was shown by the reduction in tumour incidence on the administration of phenobarbitone simultaneously with acetylaminofluorene, 4-dimethyl aminoazo benzene and diethylnitrosamine. But no such protective effect is seen if the phenobarbitone is administered after treatment with these carcinogens. In fact the number of tumours is enhanced presumably due to preferential stimulation of the growth of malignant cells.
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PMID:Liver growth and tumorigenesis in rats. 28 28

Earlier studies indicated that the hepatocarcinogenic activity of two peroxisome proliferators (PP) Wy-14,643 and di(2-ethylhexyl)phthalate (DEHP) correlated to the degree of lipofuscin accumulation and sustained cell replication rather than the level of peroxisome induction. This study extends the comparison of peroxisome proliferation, lipofuscin accumulation and cell replication responses in rats fed (i) clofibric acid at 5000 p.p.m. (CA), a regimen of moderate hepatocarcinogenicity; (ii) Wy-14,643 at 50 p.p.m. (WYLD), a dose of unknown hepatocarcinogenicity; and (iii) Wy-14,643 at 1000 p.p.m. (WYHD), as the highly hepatocarcinogenic regimen. Adult male F344 rats were fed the experimental diets for 1, 2, 5, 11 or 22 weeks. Relative liver weights (% of body weight) were increased in rats fed CA (1.6- to 1.7-fold), WYHD or WYLD (2.0- to 2.7-fold), compared to controls (approximately 3%) at all time points. All rats fed CA, WYHD or WYLD had similar hepatic peroxisome proliferation at all time points with large elevations in peroxisomal enzyme activities and number, size and mean volume of peroxisomes. In contrast, hepatocytic lipofuscin accumulation differed between treatments, with a decreasing order of accumulation observed in WYHD greater than WYLD approximately equal to CA greater than controls. Replicative DNA synthesis (as assessed by nuclear labeling index, LI) in nonlesion hepatocytes was markedly elevated at 1 week by both WYHD and WYLD (45- and 40-fold over controls respectively) while CA induced a 10-fold response over controls (control LI less than or equal to 1%). From week 2 to week 22 the hepatocytic LI was sustained in WYHD and WYLD rats (8- and 4-fold over controls respectively) but not in CA-rats, as compared to controls. In contrast to the cell replication response, apoptosis was elevated only in WYHD at 22 weeks. Collectively, this study supports the conclusion that neither hepatomegaly nor peroxisome proliferation are accurate predictors of carcinogenic activity for PP. Further, these results suggest that if lipofuscin accumulation or sustained cell turnover are indicators of PP-induced carcinogenesis, then WYLD should be at least as carcinogenic as CA. The moderate carcinogenic activity of CA also suggests that additional factor(s) may be necessary besides lipofuscin accumulation and sustained cell replication to determine the ultimate carcinogenic activity of PP.
Carcinogenesis 1992 Jun
PMID:Contrasting hepatocytic peroxisome proliferation, lipofuscin accumulation and cell turnover for the hepatocarcinogens Wy-14,643 and clofibric acid. 160 Jun 4

The mitogenic effects of peroxisome proliferating agents have been implicated in their carcinogenicity. WY-14,643 stimulates an increase in hepatocellular DNA replication that persists with continued administration, but it is unclear if other peroxisome proliferators share this property. In these studies, WY-14,643 was compared to clofibric acid, nafenopin and LY171883 given to rats in the diet for up to 30 days. DNA replication in the rat liver was quantified by immunohistochemical methods after continuous s.c. infusion of bromodeoxyuridine by osmotic minipump. During the first 7 days of treatment, WY-14,643 (0.1% in diet) and nafenopin (0.05%) increased the percentage of bromodeoxyuridine-labeled hepatocytes to greater than 50%, from 3% in controls. Clofibric acid (0.5%) and LY171883 (0.3%) increased the labeling to approximately 33%. The replicative response to each of the compounds was localized primarily to the periportal region of the liver lobule. The time-course of replication induced by clofibric acid and WY-14,64.3 was examined over 3 day intervals. The peak of replication in response to clofibric acid occurred during days 4-6, whereas the effect of WY-14,643 peaked during days 1-3 and was much greater than clofibric acid. The replicative response to WY-14,643 persisted through 30 days at dietary concentrations of 0.1 and 0.005%. Nafenopin, LY171883 and clofibric acid were without effect on DNA replication on days 28-30 even though the hepatomegaly and induction of peroxisomal beta-oxidation persisted. Thus, under the conditions of these experiments, the persistent replicative effect through 30 days was unique to WY-14,643. Although sustained replication in the general population of hepatocytes may be involved in the carcinogenesis of WY-14,643, it does not appear to be a factor in the hepatocarcinogenesis of the other peroxisome proliferators.
Carcinogenesis 1991 Sep
PMID:Hepatocellular DNA synthesis in rats given peroxisome proliferating agents: comparison of WY-14,643 to clofibric acid, nafenopin and LY171883. 189 15

The organochlorine pesticide 1,1'-(2,2,2-trichloroethylidene) bis(4-chlorobenzene) (DDT) and four structural analogues (bromopropylate, chlorobenzilate, dicofol and fenarimol) were investigated for their ability to inhibit gap junctional intercellular communication both in the Chinese hamster V79 metabolic co-operation assay and in the scrape-loading/dye-transfer assay in WB-F344 rat liver epithelial cells. The pesticides were also studied for their ability to enhance the development of gamma-glutamyltranspeptidase-positive altered hepatic foci and induce cytochrome P450 monooxygenase isoenzymes in nitrosamine-initiated male Sprague-Dawley rats. The in vitro studies showed all organohalogens except fenarimol to be potent inhibitors of cell-cell communication in both test systems used. Concomitant results were recorded in the in vivo study. Thus, all potent inhibitors of intercellular communication were found to enhance significantly foci development and fenarimol was again without any significant effect. All pesticides studied were shown to be potent inducers of the phenobarbital-inducible cytochrome P450b isoenzyme and to cause hepatomegaly. Thus, no strict correlation between cytochrome P450b induction/liver growth and tumour promotion-related effects in vivo and in vitro was apparent for these organohalogen pesticides in the present study.
Carcinogenesis 1990 Aug
PMID:Promotion of altered hepatic foci development in rat liver, cytochrome P450 enzyme induction and inhibition of cell-cell communication by DDT and some structurally related organohalogen pesticides. 238 28

Peroxisome proliferators are a class of non-mutagenic hepatocarcinogens, which induce a similar pleiotropic response such as hepatomegaly, proliferation of the peroxisomes in hepatocytes and hepatocarcinogenesis. Peroxisome proliferators are not detectable by the Ames assay and various other short-term tests. Recently a system for intrachromosomal recombination in yeast (DEL) has been shown to be inducible by a variety of non-mutagenic carcinogens. These include many carcinogens that are not detectable by the Ames assay or by various other short-term tests. In the present study the peroxisome proliferators [4-chloro-6-(2,3-xylidino)-2-pyrimidinyl-thio]acetic acid (Wy-14,643); methyl-2-[4-(p-chlorophenyl)phenoxy]2-methyl propionate (methyl clofenopate); 2-methyl-2[p-(1,2,3,4-tetrahydro-1- naphthyl)phenoxy]-propionic acid (nafenopin); 2-[4-(2,2-dichlorocyclopropyl)phenoxy]2-methyl-propionic acid (ciprofibrate); [4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio(N-beta-hydroxyethyl)-acetam ide] (BR-931); and ethyl alpha-p-chlorophenoxyisobutyrate (clofibrate) have been tested for their potential to induce DEL as well as interchromosomal recombination in yeast. No evidence for induction of either system has been found in the presence or the absence of the supernatant (S9) from rat liver homogenate. The data support the notion that peroxisome proliferators are truly non-mutagenic carcinogens.
Carcinogenesis 1990 Jan
PMID:Effect of peroxisome proliferators on intrachromosomal and interchromosomal recombination in yeast. 240 57

To determine if the carcinogenic potential of peroxisome proliferators is dependent upon their ability to induce cell proliferation, we have investigated the extent of cell proliferation in the livers of rats fed ciprofibrate, a peroxisome proliferator. Male rats were maintained on a diet containing ciprofibrate (0.025% w/w) and killed at selected intervals following 1 week of continuous [3H]thymidine labeling. Evaluation of labeling indices demonstrated a significant increase in cell proliferation during the first week but not in rats killed at the end of 5 and 20 weeks of treatment. Increases in hepatocyte nuclear labeling were found at 40 and 70 weeks of ciprofibrate administration which coincided with the appearance in livers of putative preneoplastic and neoplastic lesions. In a short-term feeding study, ciprofibrate and ethoxyquin were fed to rats at a dietary concentration of 0.025% and 0.5%, respectively, either alone or in combination for 7 days. Ciprofibrate and ethoxyquin either alone or in combination produced marked hepatomegaly and a significant increase in DNA synthesis as demonstrated by [3H]thymidine incorporation and autoradiographic studies. DNA synthesis in the group receiving ciprofibrate and ethoxyquin simultaneously, was slightly more than in animals that received either compound alone, suggesting a synergistic effect, although chronic feeding of these agents together resulted in inhibition of liver carcinogenesis (Rao, M. S. et al. (1984) Cancer Res., 44, 1072-1076). The results of this study further suggest that cell proliferation induced by peroxisome proliferators may be less important in carcinogenesis than peroxisome proliferation induced by these compounds.
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PMID:Evaluation of liver cell proliferation during ciprofibrate-induced hepatocarcinogenesis. 263 30

13 patients with extrahepatic bile duct carcinoma treated in our institute from 1960 to 1986 are reported. All were proven by pathology. There were 10 moderately differentiated or mucin adenocarcinomas, 2 poorly differentiated and 1 undifferentiated cancers. There were 9 males and 4 females with an average age of 60.6 years. Progressive obstructive jaundice was the most common presenting symptom (11/13). Hepatomegaly was found in 7 patients, distended gallbladder in 4 and gallstone in 2. Before operation, 10 patients were misdiagnosed as hepatitis, cholecystitis or cholelithiasis. During operation, regional lymph node metastasis was observed in the majority of patients. Palliative operation was performed in 10 patients and radical surgery in 3. Three received operation plus postoperative radiotherapy. None survived more than two years. The lesions occurred frequently in the upper bile duct (8 patients). The middle bile duct and diffuse type carcinomas comprised 2 each. One was not recorded clearly. The prognosis is related to the gross type of the tumor and differentiation degree. Finally, carcinogenesis is discussed briefly.
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PMID:[Carcinoma of the extrahepatic bile duct--report of 13 patients]. 285 Jan 47

Di-n-octyl phthalate (DOP) is the straight chain isomer of di(2-ethylhexyl) phthalate (DEHP) which is a widely used plasticizer and an environmental contaminant. DEHP is a strong inducer of peroxisome proliferation in rat liver. This is significant since other compounds which are strong inducers of peroxisome proliferation have been reported to be weak carcinogens (Reddy, J.K. and Lalwani, N.D., CRC Crit. Rev. Toxicol., 12 (1983) 1). In contrast to DEHP, DOP causes little or no induction of liver peroxisomes (Mann, A.H. et al., Toxicol. Appl. Pharmacol., 77 (1985) 116, and Gray, T.J.B. et al., Toxicology, 28 (1983) 167). In the current study the ability of 1% DOP to promote the development of putative preneoplastic lesions was evaluated. The effect of feeding 0.5% DEHP as well as equimolar amounts of its 2 major metabolites, mono(2-ethylhexyl)phthalate (MEHP) and 2-ethylhexanol (2-EH) were also investigated. GGT+ foci were initiated in the livers of Sprague--Dawley male rats with a single dose of diethylnitrosamine (DEN) following partial hepatectomy. The control group of rats was fed a semipurified diet (Co) for 10 weeks while the experimental groups received the semipurified diet containing the respective compounds. Induction of peroxisome proliferation was monitored by carnitine acetyltransferase (CAT) levels. DOP treatment resulted in a 6-fold increase in the number of GGT+ foci (20.8 +/- 4.0 vs. 3.5 +/- 1.3; P less than 0.05). This was accompanied by no change in liver weight and only a slight increase in CAT activity when compared with control animals. In contrast to DOP, 2-EH produced essentially no effect with regard to number of foci, peroxisome proliferation or liver weight. DEHP and MEHP induced significant peroxisome proliferation and hepatomegaly but the number of foci were significantly lower than in 2-EH-treated rats. The mechanism for the promoting ability of DOP is not clear but would not appear to be related to peroxisome proliferation. Because of the close similarity of chemical structure and metabolism between DOP and DEHP, it is possible that studies to define the mechanism of DOP induced promotion might also serve to further clarify the mechanism of DEHP induced carcinogenesis.
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PMID:Di-n-octyl phthalate (DOP), a relatively ineffective peroxisome inducing straight chain isomer of the environmental contaminant di(2-ethylhexyl)phthalate (DEHP), enhances the development of putative preneoplastic lesions in rat liver. 287 11

The effect of prolonged dietary administration of the peroxisome proliferating plasticizer di(2-ethylhexyl)phthalate (DEHP) was studied on liver carcinogenesis initiated by N-2-fluorenylacetamide (FAA) and compared with that of the neoplasm-promoter phenobarbital (PB). Also, DEHP was studied as an initiator by giving it in place of FAA before PB. Male rats were fed FAA for 7 weeks to induce hepatocellular altered foci, and were subsequently given no chemical, 12,000 p.p.m. DEHP or 500 p.p.m. PB for 24 weeks in the diet. In the rats fed DEHP, substantial hepatomegaly and peroxisome proliferation were induced. No evidence of induction of hepatocellular altered foci or hepatic neoplasms was found either when DEHP was given alone for 24 weeks or for 7 weeks followed by PB. Also, DEHP fed for 24 weeks had no promoting effect on liver altered foci that were induced by FAA and produced little or no enhancement of the occurrence of FAA-induced liver neoplasms. In contrast, PB exerted a marked enhancing effect on foci and substantially increased the incidence and multiplicity of liver neoplasms. Thus, the findings demonstrate that DEHP did not have either a rapid initiating activity, a significant sequential syncarcinogenic activity, or a promoting effect on liver carcinogenesis under conditions in which numerous agents with such activities have been identified.
Carcinogenesis 1987 Jul
PMID:Lack of rapid initiating, promoting or sequential syncarcinogenic effects of di(2-ethylhexyl)phthalate in rat liver carcinogenesis. 359 21


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