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)

Male Sprague-Dawley rats maintained on either normal diet (N) or on a diet containing phenobarbital (PB; 225 ppm) or mirex (M; 10 ppm) for 15 days received either corn oil or 1 single administration of a protective dose of CCl4 (0.3 ml/kg, po) on day 16. At 24, 48, 72, 96, or 144 hr after the protective dose, a high dose of CCl4 (5 ml/kg, po) was administered to rats of all the groups, and they were observed for 14-day lethality. In a second experiment, in rats maintained on N, PB, or M diet, liver microsomal cytochromes P-450, aminopyrine demethylase, and aniline hydroxylase were measured at various time points after the administration of the protective dose of CCl4. Serum aspartate transaminase, alanine transaminase, and sorbitol dehydrogenase elevations and histopathological changes observed under a light microscope were used as toxic end points to assess hepatotoxicity. Autoprotection was 100% when the high dose was given at 24 hr after the protective dose in N rats, whereas it was only 55% in PB- or M-pretreated rats. For later time points of 48, 72, and 96 hr, autoprotection was only around 50% in N rats, whereas it was almost 100% in PB- and M-pretreated rats. When the high dose was administered at 144 hr after the protective dose, autoprotection further declined to 25% in N rats and to 75% in M-treated rats, but it remained at 100% in PB-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of phenobarbital and mirex pretreatments on CCl4 autoprotection. 781 19

The effects of anabolic-androgenic steroid administration and exercise training on various aspects of hepatic function were investigated in sedentary and trained (treadmill for 12 wk) male and female rats treated orally with fluoxymesterone or methylandrostanolone (2 mg.kg-1 body weight, 5 d.wk-1 for 8 wk). The mean values of serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total and direct bilirubin, and total- and high-density lipoprotein-cholesterol remained within normal range in all groups of male animals. The same is true for female rats, except for an increase in alkaline phosphatase activity in the steroid-treated groups. Hepatic microsomal aniline p-hydroxylase activity was reduced in male and increased in female rats by either steroid, whereas no significant effect was detected on 7-ethoxycoumarin deethylase activity. The levels of cytochrome P-450 and cytochrome b5 were markedly decreased by the anabolic-androgenic steroid treatment in male rat microsomes, but neither the steroid administration nor exercise training induced significant changes in the cytochrome levels of female rat livers. Taking into account the significant increase in microsomal protein yield elicited by fluoxymesterone or methylandrostanolone treatment both in males and females, it is noteworthy that the total monooxygenase activities and cytochrome P-450 content, expressed on a per gram liver basis, were significantly increased in female whereas they were apparently unchanged in male rats. In conclusion, the present data show that the prolonged ingestion of high doses of anabolic-androgenic steroids, either with or without concurrent exercise training, can modify in a sex-dependent manner the capacity of rat liver to metabolize drugs without affecting classical serum indicators of hepatic function.
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PMID:Effect of training and anabolic-androgenic steroids on drug metabolism in rat liver. 835 Jul 4

Rifampicin conferred significant protection against carbon tetrachloride (CCl4)-induced liver injury. Serum alanine transaminase (ALT) and aspartate transaminase (AST) activities were not markedly altered and only hepatocellular fatty degeneration was found in mice pretreated with rifampicin (200 mg/kg), whereas severe centrilobular necrosis was observed and serum ALT and AST activities were as high as 281 and 271 I.U./l, respectively, in the control group following administration of CCl4 (400 microliters/kg). The contents and activities of microsomal drug-metabolizing enzymes in rifampicin-pretreated animals were also much higher than those of the controls. CCl4-mediated malondialdehyde (MDA) formation was increased in rifampicin-treated liver microsomes, demonstrating that rifampicin was capable of increasing the NADPH-dependent metabolism of CCl4 catalyzed by P-450 2E1 to produce free radicals. However, MDA formation was obviously depressed by rifampicin at varying concentrations from 2 to 32 x 10(-6) M in an in vitro cytochrome P-450 (P-450) enzyme system. On the other hand, NADPH oxidation in the metabolism of CCl4 and aniline hydroxylation were not suppressed in the presence of rifampicin in this systems, suggesting that rifampicin did not influence the biotransformation of CCl4 by P-450 2E1 in vitro. Therefore, the protective effect of rifampicin against CCl4 hepatotoxicity appeared to result from the direct inhibition of lipid peroxidation generated by CCl4-derived free radicals.
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PMID:Protective effect of rifampicin against acute liver injury induced by carbon tetrachloride in mice. 878 35

The purpose of this investigation was to determine the effects of experimental dicrocoeliosis on the hepatic oxidative drug-metabolizing system in hamsters. Studies were carried out 80 and 120 days after infestation with an oral dose of 40 metacercariae of Dicrocoelium dendriticum. The parasitic pathology was ascertained by detection of the fluke eggs in faeces, increased serum alanine aminotransferase and aspartate aminotransferase activities, and postmortem and histological findings. Cytochrome P-450 concentration, aniline hydroxylase activity and ethoxycoumarin O-deethylase activity were significantly decreased in both groups of infected animals. Aminopyrine N-demethylase activity and erythromycin N-demethylase activity were only reduced 120 days after infection. Effects on drug metabolizing enzymes were unrelated to changes in the physical state of the microsomal membrane, as assessed by measurement of fluorescence polarization. The results of this study indicate that the capacity of the liver for handling drugs and xenobiotics may be impaired as a consequence of dicrocoeliosis.
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PMID:Effects of experimental dicrocoeliosis on oxidative drug metabolism in hamster liver. 898 69

The present study reports on the effects of horminone on serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, on hepatic cytochrome P450 (P450) and cytochrome b5 (cyt b5) contents and on the activities of NADPH-cytochrome P450 reductase (NR), mixed function mono-oxygenases (MFO), glutathione-S-transferase (GST) and glutathione reductase (GR) of Wistar male rat. Horminone is a diterpenoid quinone (7,12-dihydroxyabiet-8,12-diene-11,14-dione) present in several species of the Labiatae family and used as medicinal plants in folk medicine. In this study, horminone was administered by the intraperitoneal route (i.p.) at a concentration of 1 or 10 mg/kg to each group of six mice, using water as a vehicle. On the one hand, results showed that horminone increased serum ALT and AST levels and cyt b5 content and induced the activities of ethylmorphine N-demethylase (EMD). On the other hand, horminone decreased P450 content and inhibited the activities of 7-ethoxyresorufin O-deethylase (ERD), 7-ethoxycoumarin O-deethylase (ECD), aniline 4-hydroxylase (AH) and NR. Based on these results, the possibility of toxic effects occurring after administration of plant extracts containing horminone must be considered.
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PMID:Effects of horminone on liver mixed function mono-oxygenases and glutathione enzyme activities of Wistar rat. 932 1

The protective effects of alpha-Hederin on carbon tetrachloride-induced hepatotoxicities were investigated in mice. Pretreatment with alpha-Hederin prior to the administration of carbon tetrachloride significantly prevented the increase in serum alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) activity and lipid peroxidation in a dose dependent manner. Hepatic glutathione levels and glutathione-S-transferase activities were not affected by pretreatment with alpha-Hederin alone but pretreatment with alpha-Hederin protects carbon tetrachloride-induced depletion of hepatic glutathione levels. The effects of alpha-Hederin on the cytochrome P450 (P450) 2E1, the major isozyme involved in carbon tetrachloride bioactivation were investigated. alpha-Hederin markedly decreased the P450 2E1-specific activities of p-nitrophenol and aniline hydroxylation in a dose-dependent manner. Consistent with these observations, the P450 2E1 expressions were also decreased, as determined by immunoblot analysis. These results demonstrate that treatment of mice with alpha-Hederin decreases the expression and activities of P450 2E1 enzyme, and reduces biotransformation of carbon tetrachloride, and diminished carbon tetrachloride-induced liver injury.
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PMID:The prevention of carbon tetrachloride-induced hepatotoxicity in mice by alpha-hederin: inhibiton of cytochrome P450 2E1 expression. 963 40

1. Thonningia sanguinea, a plant used prophylactically against bronchial asthma in Ghana was recently found to have antioxidative and hepatoprotective actions in our laboratory. 2. In this study, the effect of T. sanguinea extract on certain biochemical indices in serum and liver of Fischer 344 rats given a single intraperitoneal (i.p.) dose (1 mg/kg) of aflatoxin B1 (AFB1) was investigated. 3. Administration of AFB1 resulted in significant increases in serum alanine aminotransferase (ALT) and glutathione S-transferase (GST) levels and a significant decrease in aniline hydroxylase activity in liver microsomes. When T. sanguinea (5 ml/kg) was intraperitoneally administered to rats 12 h and 1 h before AFB1, liver injury was significantly reduced as seen in the decreased levels of serum ALT and serum GST. However, the decrease in aniline hydroxylase activity by AFB1 was not recovered but enhanced by T. sanguinea pre-treatment. 4. Kinetic analysis of cytochrome P450 activity of rat liver microsomes in vitro demonstrated that T. sanguinea inhibited aniline hydroxylase non-competitively suggesting depression of biotransformation of AFB1 to toxic metabolites. 5. The data indicate a hepatoprotective action of T. sanguinea against AFB1-induced liver injury.
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PMID:Medicinal herb, Thonningia sanguinea protects against aflatoxin B1 acute hepatotoxicity in Fischer 344 rats. 975 33

Aim of this study was to determine and further characterize the serum aminopeptidase-M in children with liver diseases. Based on our new assay, we have shown two fractions of the enzyme. Activity of the first fraction is expressed in undiluted serum at pH adjusted from 8.5 (pH of storaged serum) to 7.4. Activity of the second fraction (cryptic activity) appears in the serum (pH 7.4) as a result of dilution and/or addition of aniline naphthalene sulfonic acid. In children with Alagille syndrome, extrahepatic biliary duct atresia, Byler's disease, and acute hepatitis due to hepatitis B virus infection, activities of both fractions are highly elevated as compared to healthy children or those with chronic viral hepatitis. Moreover, serum aminopeptidase-M seems to reflect other aspects of the pathological process than those reflected by the alanine aminotransferase and gamma-glutamyltranspeptidase. Due to increased activity and broad substrate specificity, the enzyme seems to be also a cofactor of cholestasis and hepatitis.
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PMID:Further studies on aminopeptidase-M in blood in children with cholestatic liver diseases and viral hepatitis. 995 39

The protective effects of oleanolic acid on carbon tetrachloride-induced hepatotoxicities and the possible mechanisms involved in this protection were investigated in mice. Pretreatment with oleanolic acid prior to the administration of carbon tetrachloride significantly prevented the increase in serum alanine aminotransferase and lactate dehydrogenase activity and liver lipid peroxidation in a dose-dependent manner. Hepatic glutathione levels and glutathione-S-transferase activities were not affected by treatment with oleanolic acid alone but pretreatment with oleanolic acid protects carbon tetrachloride-induced depletion of hepatic glutathione levels. The effects of oleanolic acid on the cytochrome P450 (P450) 2E1, the major isozyme involved in carbon tetrachloride bioactivation were investigated. Treatment of mice with oleanolic acid resulted in a significant decrease of P450 2E1-dependent p-nitrophenol and aniline hydroxylation in a dose-dependent manner. Consistent with these observations, the P450 2E1 expressions were also decreased, as determined by immunoblot analysis. These results show that the protective effects of oleanolic acid against the carbon tetrachloride-induced hepatotoxicity may, at least in part, be due to its ability to block bioactivation of carbon tetrachloride mainly by the inhibition of expression and activities of P450 2E1.
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PMID:Inhibition of cytochrome P450 2E1 expression by oleanolic acid: hepatoprotective effects against carbon tetrachloride-induced hepatic injury. 1035 42

In the mouse, retinol administration attenuates carbon tetrachloride (CCl4)-induced hepatic injury. We have investigated the role of cytochrome P4502E1 (CYP2E1) in this interaction. Male Swiss Webster mice were administered retinol (75 mg/kg/d) or vehicle for 3 days prior to CCl4 (30 microl/kg, ip). Hepatotoxicity produced by CCl4 was assessed by plasma alanine aminotransferase (ALT) activity and light microscopy (ALT activity of 1391+/-430 vs. 274+/-92 IU/L for vehicle + CCl4 and retinol + CCl4 treatments respectively, p < 0.05). Retinol's attenuation of liver injury was maintained when CCl4 was administered 48 h after the conclusion of the retinol pretreatment. Aniline hydroxylation activity, an indicator of CYP2E1 catalytic activity, determined on day 4 was 33.8% of untreated control in vehicle + CCl4 treatments while the retinol + CCl4 treatment group was 94.2% of untreated control. Additionally, CYP2E1 immunoreactive protein was 78% lower in vehicle + CCl4 vs. retinol + CCl4 treatment groups. Attenuation of potentiated hepatotoxicity was also observed when CYP2E1 was induced by acetone (ALT activity of 3119+/-1066 vs. 247+/-77 IU/L for vehicle and retinol treatments respectively, p < 0.05). In the mouse, retinol itself does not alter constitutive or inducible CYP2E1 expression. However, in combination with CCl4 retinol does reduce the amount of CCl4 bioactivated to its toxic metabolite. We conclude that retinol attenuates CCl4-induced hepatotoxicity by causing a decrease in CCl4 bioactivation but does not cause a decrease in CYP2E1 expression.
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PMID:Role of cytochrome P4502E1 in retinol's attenuation of carbon tetrachloride-induced hepatotoxicity in the Swiss Webster mouse. 1056 6


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