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)

Although butylated hydroxytoluene (BHT) is non-mutagenic, at high doses it has recently been associated with an increased incidence of liver tumours in laboratory rodents. To establish whether chronic liver cell injury may be involved in the genesis of these tumours, BHT was administered to rats by orogastric gavage at doses of 0, 25, 250 or 500 mg/kg/day for up to 28 days and also at daily doses of 1000 and 1250 mg BHT/kg for up to 4 days (sublethal doses). The sublethal doses induced centrilobular necrosis within 48 hr, whereas administration of BHT for 7 or 28 days caused dose-related hepatomegaly and at the highest dose level induced progressive periportal hepatocyte necrosis. The periportal lesions were associated with proliferation of bile ducts, persistent fibrous and inflammatory cell reactions, hepatocyte hyperplasia and hepatocellular and nuclear hypertrophy. Biochemical changes consisted of dose-related induction of epoxide hydrolase, dose-related changes in the ratio of cytochrome P-450 isoenzymes and depression of glucose-6-phosphatase. Measurement of BHT demonstrated a dose-related accumulation in fat but not in the liver. Changes in hepatic activating and detoxifying enzyme profiles are implicated both in the mechanism of periportal hepatocyte damage and in the change of site of damage according to the dose and duration of the treatment. The persistent and active nature of the lesions in rats dosed with 500 mg BHT/kg for 28 days, combined with evidence of cell damage at doses equivalent to those associated with hepatic tumours (250 mg BHT/kg), suggests that chronic liver cell damage may be involved in their aetiology. In this and several other studies, there was no evidence that BHT causes liver damage at a dose level of 25 mg/kg/day. As this is several hundred times higher than the normal human intake, it is considered unlikely that BHT poses a threat to human health.
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PMID:Hepatic responses to the administration of high doses of BHT to the rat: their relevance to hepatocarcinogenicity. 302 37

Ammonium perfluorooctanoate (APFO) is known to induce a striking hepatomegaly in rats. The purpose of these studies was to determine the causes of the hepatomegaly and compare the effect to other liver-enlarging compounds. Since the total hepatic DNA content was similar in control and APFO-treated rats, the hepatomegaly represented a hypertrophic rather than a hyperplastic response. The cytochrome P-450 content and activity of benzphetamine N-demethylase increased in the livers of APFO-treated rats, indicating the proliferation of the smooth endoplasmic reticulum. In contrast to the membrane-bound enzymes, the soluble enzymes glutathione S-transferase and UDPglucuronyltransferase were unaffected by APFO treatment. The activity of carnitine acetyltransferase was disproportionately increased relative to carnitine palmitoyltransferase in the livers of APFO vs that in control rats, confirming the predominant proliferation of peroxisomes vs that of mitochondria. Morphological studies confirmed the proliferation of the endoplasmic reticulum, mitochondria, and peroxisomes in the livers of APFO-treated rats. In contrast to many other peroxisome proliferating agents, APFO did not possess hypolipidemic activity.
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PMID:Biochemical and morphological studies of ammonium perfluorooctanoate-induced hepatomegaly and peroxisome proliferation. 360 46

The short-term effects of citral on the liver have been studied in two strains of rat. Hepatomegaly was accompanied in citral-treated rats by an altered distribution of lipid and glycogen in the liver and peroxisome proliferation occurred in a manner reminiscent of that associated with some hypolipidaemic compounds. Specific biochemical markers supported the morphological changes in the peroxisomes. Cyanide-insensitive palmitoyl CoA oxidation showed, at the maximum, fourfold and threefold inductions in Wistar albino and Long Evans hooded rats, respectively. In addition, induction of cytochrome P-450 levels was greater in the Long Evans than in the Wistar rats, the maximal increases recorded being 81 and 27% respectively. A peroxisome-associated polypeptide of molecular weight 80,000 daltons (PPA-80) was induced, especially in Long Evans rats. No alterations in plasma triglycerides or total cholesterol were detected. The differential induction of the mixed-function oxidase system and the differential proliferation of peroxisomes in these two strains of rat suggest that citral may be metabolized differently in the two strains. The study indicates that peroxisomal and possibly also mitochondrial changes are involved in the action of citral on lipid metabolism.
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PMID:Comparison of the short-term hepatic effects of orally administered citral in Long Evans hooded and Wistar albino rats. 362 39

The hypolipidemic activity of tiadenol-disulfoxide, the major metabolite of 1,10-bis(hydroxyethylthio)decane (tiadenol, Eulip) in man and in the rat was assessed in various experimental models versus the corresponding activity of tiadenol. Tiadenol-disulfoxide in the normolipidemic rats lowers total serum cholesterol and serum and liver triglycerides in an extent comparable to that of the reference compound. Likewise, it is equally effective as tiadenol in preventing Triton-induced hyperlipidemia and Nath diet induced hypercholesterolemia; in addition tiadenol-disulfoxide is slightly more effective than tiadenol in increasing HDL-cholesterol in hypercholesterolemic rats. At hypolipidemic doses the compound causes no hepatomegaly, no induction of peroxisomal catalase and palmitoyl-CoA oxidase activities, no smooth endoplasmic reticulum proliferation and no induction of microsomal cytochrome P-450 and of cytochrome P-450 dependent enzyme activities: aminopyrine (aminophenazone) N-demethylase, aniline hydroxylase, zoxazolamine hydroxylase and hexobarbital oxidase. At the suprapharmacological dose of 300 mg/kg tiadenol-disulfoxide, if compared to the reference compound, shows a generally lower order of toxicity on these hepatic parameters. Orally administered tiadenol-disulfoxide is well absorbed by the gastrointestinal tract and is eliminated in urine at 45% of the dose in unchanged form, and the remaining being: glucuron-conjugated tiadenol-disulfoxide (10%), S-oxidized metabolites (15%) and sulfoxidized carboxylic metabolites (15%). The compound is well tolerated both in mice and rats. The results of this comparative study demonstrate that: 1. tiadenol-disulfoxide is a substance with promising hypolipidemic properties; 2. tiadenol-disulfoxide is largely responsible for the hypolipidemic activity of tiadenol; 3. hepatomegaly consequent to tiadenol administration is the consequence of the response of the liver cell to the increased functional demand of the mixed function oxidase (MFO) system involved in the metabolism of the drug; 4. peroxisomal enzyme activities induction observed with both drugs at non-pharmacological doses does not play any role in their hypolipidemic action and is not associated with hepatomegaly.
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PMID:Experimental studies on pharmacology, metabolism and toxicology with tiadenol-disulfoxide. Dissociation of lipid lowering effects and the induction of peroxisomal and microsomal drug-metabolizing enzymes. 366 66

The widely used benzodiazepine tranquilizers diazepam and oxazepam promoted development of hepatocellular hyperplastic foci and hepatocellular neoplasms (adenomas and carcinomas) when they were fed in diet to male B6C3F1 mice after initiation by N-nitrosodiethylamine. Diazepam was more effective than oxazepam and its effect was proportionate to dose. Both diazepam and oxazepam induced hepatomegaly, cytochrome P-450 and cytochrome P-450-dependent aminopyrine N-demethylase activity in hepatocytes, effects similar to those produced by a well-known rodent liver tumor promoter, phenobarbital. In view of the importance and widespread use of this class of compounds, more work is warranted to examine their effects on tumor development in different mammalian species.
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PMID:Tumor-promoting activity of benzodiazepine tranquilizers, diazepam and oxazepam, in mouse liver. 369 6

Compound LY171883 caused dose-related and reversible hepatomegaly in male Fischer 344 rats. Histological examination revealed hepatocellular hypertrophy with no other evidence of liver disease. There were only minor changes in serum glucose, total bilirubin, alkaline phosphatase, and alanine transaminase which were generally unrelated to dose and dissociable from the hepatomegaly. Total liver DNA increased but the DNA concentration decreased, indicating that liver growth involved a combination of hypertrophy and hyperplasia. Total liver protein and RNA increased. Hepatic mitochondrial protein content increased but cytochrome oxidase activity was not changed. There were minor changes in mitochondrial respiratory parameters; however, all the values were in the normal range and there was no indication of mitochondrial toxicity. Microsomal protein, drug-metabolizing activity, and cytochrome P-450 increased, but glucose-6-phosphatase activity was not changed. The induction of drug-metabolizing enzymes and absence of toxicity were evidence that the hepatomegaly was an adaptation to an increased functional load in the liver. An increase in catalase activity suggested that the response may have also involved peroxisomes. In addition to rats, LY171883 administration caused hepatomegaly in mice and hamsters at daily exposures exceeding 100 mg/kg. The response was not observed in guinea pigs, beagle dogs, or rhesus monkeys given maximum tolerated doses, indicating LY171883-induced hepatomegaly is not a response common to all species. The doses required to elicit hepatomegaly greatly exceeded doses that produce pharmacological efficacy in animals and those that are expected to be used clinically. Since humans will not receive doses comparable to those given rodents, and considering that the primate species tested did not experience hepatomegaly, it is unlikely that the effect observed in rodents can be extrapolated to humans.
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PMID:Characterization of liver enlargement induced by compound LY171883 in rats. 384 Jan 8

Liver regeneration was stimulated in male rats with two-thirds of the liver removed by feeding a basal diet supplemented with acetaminophen (0.35-1.5%; weight basis), 2-acetamidophenol (1.0%) and acetophenetidin (1.0%) over a period of 10 days po, but was in the control range with the m-isomer, 3-acetamidophenol (1.0%), N-butyryl-p-aminophenol (1.0%), o-, m- and p-aminophenols (0.50%) and 4-acetamidothiophenol. In fact, the latter inhibited at a level of 0.60%. The operated young or mature female underwent no significant increase in control response with acetaminophen (1-1.5%). However, as with the male, the wet and dry liver weight percentages were markedly increased in the intact female fed acetaminophen (1.0-1.5%) as also with 2-acetamidophenol (1.0%). Liver enlargement occurred in the intact male with acetophenetidin (1.0%) but not with the N-butyryl- and thiophenol derivatives fed at 1.0 and 0.50%, respectively. Hepatic microsomal preparations from the intact and operated series showed no remarkable changes in cytochrome P-450 nor in the enzymes, aminopyrine demethylase and benzo[a]pyrene hydroxylase, with the more polar acetaminophen and the N-butyryl compound but the enzymes were elevated in the group fed acetophenetidin. Inductive effects on microsomal enzymes were further amplified by injection of several animals per group with phenobarbital ip daily at 80 mg/kg for the last 3 days prior to sacrifice. Increases in increments or liver weight percentages ensued over the basal values and as investigated in an intact male series, the enzymes ranged higher than the uninjected controls and with the thiophenol-fed group, exceeded those of the phenobarbital-injected controls.
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PMID:Liver regeneration and hepatic microsomal enzyme induction by acetaminophen and derivatives. 402 13

The antilipolytic drug acipimox (5-methylpyrazine-2-carboxylic acid 4-oxide) was given to male rats for 1 week at 500, 1000 and 2000 mg/kg/day and for 2, 6 and 7 months at 20, 100 and 500 mg/kg/day. The peroxisome proliferative effect was evaluated determining the activity of catalase and carnitine acetyltransferase, the rate of cyanide-insensitive palmitoyl CoA oxidation and the electrophoretic profile of liver polypeptides. Hepatic lipid content and distribution were evaluated after 2 and 6 months' treatment. The effect on liver detoxificating function was evaluated by assaying glutathione, cytochrome P-450, glutathione-S-transferase and glutathione-reductase activities after 7 months' treatment. Sub-acute and chronic treatment with a wide range of acipimox doses did not cause hepatomegaly, liver peroxisome proliferation or liver steatosis and did not change some important biochemical variables related to detoxification and biotransformation mechanisms. Acipimox given to rats does not have the negative side-effects of other compounds and seems a safe blood lipid lowering drug.
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PMID:Effect of the antilipolytic compound acipimox on peroxisome marker enzymes, lipid pattern and biotransformation related functions in rat liver. 407 Mar 42

Significant declines in the non-induced activities of liver microsomal drug-metabolizing enzymes and in the amount of cytochrome P-450 occur between maturity (16 months) and senescence (27 months) in male Fischer 344 rats, whereas there are essentially no differences between very young (1 month) and mature animals. Several hepatic responses to chronic phenobarbital administration also demonstrate marked age-dependent changes. The livers of young and mature animals exhibit: (1) greater hepatomegaly; (2) faster rates of induction and post-induction recovery of microsomal mixed function oxidase enzyme activities and hemoprotein concentration; and (3) higher maximally induced levels of these components in comparison to senescent rats. When considered with information from previous studies, the present data suggest that the age-related decline in liver drug metabolism may be due to qualitative and/or quantitative changes in the structural and/or functional components of the hepatic microsomal mixed function oxidase system.
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PMID:Effects of aging and phenobarbital on the rat liver microsomal drug-metabolizing system. 678 36

The activity of microsomal cytochrome P-450 monooxygenase and ultrastructure of the liver have been studied in rats exposed dynamically to 50, 500, and 20,000 ppm of vinyl chloride (VC) over 10 months. After 1 and 3 months of exposure to 500 and 20,000 ppm of VC, the level of cytochrome P-450 was slightly lower than in the control animals and upon continuation of exposure it was restored to the original level accompanied by slight increase of activity of aniline p-hydroxylase. Liver enlargement, developed in the course of the exposure, was accompanied by ultrastructural alterations beginning in the 3rd month of exposure to all concentrations of VC. Development of hepatic alterations (hypertrophy of smooth and rough endoplasmic reticulum, swelling of mitochondria, accumulation of lipid droplets, focal cytoplasmic degradation) is discussed with regard to the activity of microsomal monooxygenase system in metabolizing VC to toxic metabolites.
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PMID:Monooxygenase activity and ultrastructural changes of liver in the course of chronic exposure of rats to vinyl chloride. 745 Aug 89


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