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

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Query: EC:2.6.1.2 (alanine aminotransferase)
26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In rats, 3 days treatment with paracetamol (1 oral dose of 1 g/kg daily) produced a complete protection against the hepatotoxic actions of a further dose of paracetamol as documented by determination of serum enzyme activities (glutamic-oxaloacetic transaminase, (GOT), glutamic-pyruvic transaminase (GPT), sorbitol dehydrogenase (SDH), bromsulphthalein retention and histological investigations. Subacute paracetamol treatment decreased liver glutathione levels by 46%, liver microsomal cytochrome P-450 content by 23%, hepatic hydroxylation of aniline by 29% and hepatic demethylation of aminopyrine by 46%. It afforded also some protection against the hepatotoxic actions of carbon tetrachloride, bromobenzene and thioacetamide, but did not influence the antiphlogistic activity of paracetamol (carrageenan paw edema test). Plasma and liver concentrations of free paracetamol after oral administration of 1 g/kg paracetamol were somewhat higher in the subacutely paracetamol-pretreated rats than in the non-pretreated control animals whereas no differences in the concentrations of conjugated paracetamol were found between the 2 groups. Pretreatment with paracetamol did not influence the urinary excretion of free paracetamol but caused some shift in the urinary excretion of paracetamol conjugates: pretreated rats excreted 23% less of the paracetamol glucuronide and sulfate and 33% more of the paracetamol mercapturate than the control animals. A depression of the microsomal mixed-function oxidase activity is presumed to be the main cause of the paracetamol-induced protection against paracetamol hepatotoxicity.
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PMID:Studies on the mechanism of paracetamol-induced protection against paracetamol hepatotoxicity. 47 30

The hepatotoxic effects of carbon tetrachloride (0.01 ml/kg i.p.), thioacetamide (50 mg/kg intraperitoneally), paracetamol (0.5 g/kg intraperitoneally), and allyl alcohol (0.05 ml/kg intraperitoneally) as estimated by determination of serum enzyme activities (GOT, GPT, SDH) were enhanced in mice treated with one oral dose of 4.8 g/kg ethanol 16 hrs. previously. Pretreatment of mice with ethanol did not increase the hepatotoxic actions of bromobenzene (0.25 ml/kg intraperitoneally), phalloidin (1.5 mg/kg intraperitoneally), alpha-amanitin (0.75 mg/kg intraperitoneally), and praseodymium (12 mg/kg intravenously) though there was a trend to higher enzyme activities in the case of bromobenzene. In guinea-pigs ethanol also aggravated CCl4-induced liver damage, but only strengthened the hepatotoxic activity of D-galactosamine (150 mg/kg intraperitoneally). Treatment with 4.8 g/kg ethanol did not influence liver glutathione levels in mice but increased aniline hydroxylation in the 9000 x g liver homogenate supernatant of mice and guinea-pigs. A dose of 2.4 g/kg ethanol, on the other hand, neither increased aniline hydroxylase activity nor enhanced carbon tetrachloride-induced hepatotoxicity in mice. It is assumed that the enhanced sensitivity to hepatotoxic agents after treatment with ethanol may be due to an enhanced microsomal activation of these substances.
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PMID:The influence of ethanol pretreatment on the effects of nine hepatotoxic agents. 56 75

2-Dimethylaminoethanol (DMAE; 0.1--0.5 g/kg) significantly reduced the paracetamol-induced increments of serum-enzyme activities (GOT, GPT, SDH) in rats and mice. This hepatoprotective effect of DMAE depended on the applied dose in rats, but there was no complete protection following the highest dose. Paracetamol-induced depletion of hepatic glutathione (GSH) was not influenced by the simultaneous administration of DMAE in rats and mice. Metabolic disposition of paracetamol in the urine of rats showed an enhanced elimination of free paracetamol and the glucuronide in the DMAE-treated group, whereas the mercapturate excretion remained unchanged. Diminished p-hydroxylation of aniline in a 9000Xg supernatant of rat and mouse liver homogenates in the presence of DMAE indicated an inhibition of microsomal mixed-function oxidase activity, which is also involved in the metabolic activation of paracetamol.
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PMID:[Influence of 2-dimethylaminoethanol on the hepatotoxicity of paracetamol in rats and mice (author's transl)]. 58 37

Male rats provided with a 5 or 15% (v/v) ethanol solution as the sole source of fluid consumed ethanol at a rate of 11.4 or 24.9% of total calories (4.2 or 8.3 g/kg daily). After ethanol consumption lasting 1, 2 and 3 weeks the hepatotoxicity of CCl4 (0.1 ml/kg i.p.) was elevated by determination of serum activities of glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase ( GPT), sorbitol dehydrogenase (SDH) and histological investigations. Carbon tetrachloride (CCl4)-induced liver damage was significantly greater in rats provided with ethanol than in the tap-water consuming controls. This potentiation of CCl4 hepatotoxicicty was fully developed already after a 1-week exposition to ethanol and was greater in the 15% than in the 5% ethanol group. Ethanol alone did not influence serum enzyme activities but increased microsomal aniline hydroxylation. There was, however, no clear-cut parallelism between potentiation of CCl4 hepatotoxicity and activation of aniline hydroxylation.
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PMID:Increased carbon tetrachloride hepatotoxicity after low-level ethanol consumption. 70

1. Aflatoxin B1 (1.5 mg/kg body weight, i.p.) was administered to rats, mice, quail and chickens to examine the comparative effect on hepatic microsomal drug-metabolizing enzymes, cytosolic glutathione S-transferase and serum enzymes. 2. Administration of aflatoxin B1 to rats resulted in a significant decrease in microsomal cytochrome P-450, NADPH-cytochrome c reductase, activities of aminopyrine N-demethylase, aniline hydroxylase, cytosolic glutathione S-transferase and liver glutathione content. However, no significant changes in these parameters were seen in mice. 3. Quail showed a significant decrease in the content of cytochrome P-450 and the activities of aminopyrine N-demethylase, aniline hydroxylase and cytosolic glutathione S-transferase. A similar treatment did not affect these biotransformation enzymes in chickens. 4. The activities of serum enzymes, sorbitol dehydrogenase, alanine aminotransferase and aspartate aminotransferase were increased significantly in rats and quail. Mice exhibited a significant increase in the activities of sorbitol dehydrogenase and aspartate aminotransferase, while chickens showed a significant increase only in alanine aminotransferase.
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PMID:Comparative assessment of the effect of aflatoxin B1 on hepatic dysfunction in some mammalian and avian species. 135 19

Aniline and its halogenated derivatives are widely used as chemical intermediates. The purpose of this study was to determine the hepatotoxic and nephrotoxic potential of the 2-haloanilines. Male Fischer 344 rats (n > or = 4) were injected (i.p.) with 1.0 or 1.25 mmol/kg of: aniline (A), 2-fluoroaniline (2-FA), 2-chloroaniline (2-ClA), 2-bromoaniline (2-BrA), 2-iodoaniline (2-IA) or vehicle (0.9% saline, 2.5 ml/kg). All compounds were injected as hydrochloride salts. Renal and hepatic function was monitored 24 h after treatment. All of the 2-haloanilines induced oliguria, diminished kidney weight, tubular casts and decreased renal cortical slice accumulation of organic anions. Blood urea nitrogen (BUN) levels were increased (P < 0.05) by treatment with 1.0 or 1.25 mmol/kg of 2-FA, 2-ClA or 2-BrA. Hepatic alterations were also observed and characterized by elevated plasma ALT/GPT activity and altered morphology in the centrilobular region. The nephrotoxic and hepatotoxic potentials were similar among the 2-haloanilines but aniline was less toxic than its 2-halo derivatives. These results demonstrated that halogen substitution at the 2-position of aniline increased hepatic and renal toxicity. However, the severity of toxicity was not influenced by the nature of the halogen substituent.
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PMID:Acute renal and hepatic toxicity of 2-haloanilines in Fischer 344 rats. 146 50

Female Wistar rats were pretreated with I ml of carbon tetrachloride/kg of body weight or with olive oil. All the rats were given this dose of CCl4 20 or 40 days later. Liver regeneration as evaluated by 3H-thymidine incorporation into liver DNA and by the number of mitotic hepatocytes was markedly impaired in CCl4-pretreated rats when compared with olive oil-pretreated controls. DNA labelling reached only 83 and 59% and mitotic index 35 and 58% of control values, respectively, at 20-day and 40-day time intervals. The variables characteristic of liver damage did not parallel the changes in cell division. About 20% of hepatocytes were necrotic both in the CCl4-pretreated and in the control rats. The activity of serum alanine aminotransferase was higher in the CCl4-pretreated rats. Only serum aspartate aminotransferase activities were somewhat lower when compared to controls. Similarly, serum aminotransferases were much less affected by the pretreatment than the markers of regeneration when two low doses of CCl4 (0.125 ml/kg) were given to rats 20 days apart. The activities of microsomal enzymes aniline hydroxylase and pethidine demethylase were equal in control and in experimental rats 20 days after CCl4 pretreatment which indicated that the effects of CCl4 were not mediated by an overall decrease in cytochrome P-450 enzymes. In summary, a single pretreatment of rats with CCl4 induced changes in liver that lasted for 40 days and impaired liver regeneration when another dose of CCl4 was applied.
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PMID:Prolonged reduction of hepatocyte proliferative ability in rats after a single treatment with carbon tetrachloride. 157 74

This study was done to determine the relationship between microsomal lipid peroxidation during hepatic ischemia/reperfusion and alteration in cytochrome P-450-dependent drug metabolism. Rats were pretreated with alpha-tocopherol to inhibit lipid peroxidation or with vehicle (soybean oil) and then subjected to 60 min no-flow hepatic ischemia in vivo. Control animals were time-matched sham-ischemic animals. After 1, 5 or 24 hr of reperfusion, liver microsomes were isolated and cytochrome P-450 and mixed function oxidases were studied. In vehicle-treated ischemic rats, serum ALT levels peaked at 5 hr (5,242 +/- 682 U/L) and were significantly reduced by alpha-tocopherol pretreatment (1,854 +/- 229 U/L, p less than 0.01). Similarly, microsomal lipid peroxidation was elevated in the vehicle-treated ischemic group, but this elevation was prevented by alpha-tocopherol pretreatment. Microsomal cytochrome P-450 content and aminopyrine-N-demethylase activity were both decreased in vehicle-treated ischemic rats to 60% and 70% of sham-ischemic control levels, respectively. Although alpha-tocopherol restored cytochrome P-450 content to the level of sham-ischemic control rats, aminopyrine-N-demethylase activity remained at 76% of control with alpha-tocopherol treatment (p less than 0.01 compared with sham-ischemic control). In contrast to what was seen with cytochrome P-450 and aminopyrine-N-demethylase, aniline p-hydroxylase activity was elevated in the vehicle-treated ischemic rats compared with sham-ischemic control rats. These increases were prevented by alpha-tocopherol pretreatment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of alpha-tocopherol on hepatic mixed function oxidases in hepatic ischemia/reperfusion. 173 30

The pulmonary biochemical response, particularly the effects on mixed-function oxidases, was investigated in rats exposed to 40 ppm furfural for 1 h daily, 5 days per week, for periods of 7, 15 and 30 days. This concentration is ca. 22% of the acute LC50 dose. Exposure to furfural increased the activities of acid and alkaline phosphatases and glutamic-pyruvic transaminase, inhibited the activities of arginase and succinic dehydrogenases and elevated the concentration of lactic acid in the lungs. In the group of mixed-function oxidases, the activities of aminopyrene-N-demethylase and aniline hydroxylase (phase I, cytochrome P-450b specific) significantly increased and the activity of Benzo[a]pyrene hydroxylase (phase I, cytochrome P-450c specific) decreased. The activity of glutathione-S-transferase (phase II component) also was increased concurrently with a decrease in the concentration of glutathione. The magnitude of biochemical alterations in most cases was related directly to the duration of exposure. Our observations indicate that furfural caused pulmonary irritation, parenchymal injury and the regenerative proliferation of type II pneumocytes. Selective (cellular and/or cytochrome P-450 isozyme specific) enhancement of pulmonary mixed-function oxidases by furfural appears to stimulate its own pulmonary biotransformation, and the excretion of oxidative metabolites was facilitated by their enzymatic conjugation with glutathione.
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PMID:Inhalation toxicity of furfural vapours: an assessment of biochemical response in rat lungs. 178 39

Piperine, a major pungent constituent of black and red peppers, was administered to rats intragastrically and intraperitoneally to study whether it alters the activities of hepatic mixed-function oxidases (MFO) and serum enzymes as specific markers of hepatotoxicity. An intragastric dose of 100 mg/kg of piperine to adult, male Sprague-Dawley rats caused an increase in hepatic microsomal cytochrome P-450 and cytochrome b5, NADPH-cytochrome c reductase, benzphetamine N-demethylase, aminopyrine N-demethylase and aniline hydroxylase 24 h following treatment. On the other hand, a 10 mg/kg dose given i.p. exhibited no effect on the activities of the aforementioned parameters of the hepatic drug-metabolizing enzyme system. However, when the intragastric and intraperitoneal doses were increased to 800 mg/kg and 100 mg/kg, respectively, the black pepper alkaloid produced a significant decrease in the levels of cytochrome P-450, benzphetamine N-demethylase, aminopyrine N-demethylase and aniline hydroxylase 24 h after treatment. None of the treatments significantly elevated the activities of serum sorbitol dehydrogenase (SDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and isocitrate dehydrogenase (ICD), suggesting that piperine is not a hepatotoxic agent.
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PMID:Comparison of the effects of piperine administered intragastrically and intraperitoneally on the liver and liver mixed-function oxidases in rats. 189 51


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