Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.5.1.18 (glutathione S-transferase)
 22,582 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Technical hexachlorocyclohexane (HCH) depleted hepatic stores of vitamin A in male albino rats to cause secondary vitamin A deficiency. 2. Toxicity of HCH in rats is augmented by dietary vitamin A-deficiency as evidenced by growth retardation, organ hypertrophies and alterations in the serum and liver levels of the marker enzymes of toxicity. 3. Supplementation of dietary vitamin A to the rats either in adequate (2000 IU/kg diet) or in an excess but not hypervitaminotic level (10(5) IU/kg diet) resulted in significant protection against the toxicity of HCH. 4. The activities of the hepatic xenobiotic metabolizing enzymes were generally low (with the exception of glutathione S-transferase) in the vitamin A-deficient rats compared to those of the vitamin A supplemented diet groups. 5. The results indicated that dietary vitamin A influences the response of male albino rats to HCH toxicity possibly by modulating the activities of hepatic xenobiotic metabolizing enzymes.
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PMID:Effect of vitamin A on hexachlorocyclohexane (HCH) toxicity in the rat. 128 38

Weanling rats were kept on a synthetic vitamin A free diet for 9 weeks, and subsequently on the same diet but with oral supplementation of vitamin A palmitate at different doses for 2-3 weeks. The ability of liver microsomes to catalyze reactions of aflatoxin B1 (AFB1) leading to its activation and DNA adduct formation was measured after each period of experimental feeding. An increased molecular reactivity of AFB1 was evident during vitamin A deficiency such that the degree of its conversion to its reactive metabolite and subsequent DNA adduct formation was higher with microsomes from vitamin A-deficient rats as compared to rats maintained on normal supply of vitamin A. These activities of microsomes returned to normal after the rats had adequate supplements of vitamin A. The vitamin A status was also found to play a role in regulating glutathione S-transferase activity of the liver cytosol fraction, the activity being low in deficiency but increased progressively with increasing supplementation of vitamin A. Results suggest that vitamin A can afford protection against adverse effects of the potent hepatocarcinogen AFB.
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PMID:In vivo effect of dietary factors on the molecular action of aflatoxin B1: role of vitamin A on the catalytic activity of liver fractions. 249 33

Feeding of vitamin A-deficient diet to male weanling rats for 10 weeks caused significant reduction in the hepatic cytochrome P-450, cytochrome b5, aminopyrine N-demethylase and arylhydrocarbon hydroxylase activities. Contrary to this, the levels of these Phase I enzymes were found to be significantly elevated in all the 3 portions (proximal, middle and distal) of the intestine in deficient animals as compared to corresponding pair-fed controls. Of the Phase II enzymes studied, UDP-glucuronyltransferase showed a significant decrease whereas glutathione S-transferase showed a significant increase in vitamin A-deficient rat liver and small intestine. The study suggests that vitamin A deficiency causes an imbalance between the Phase I and phase II drug metabolizing enzyme systems which may decrease the capacity of the organism to withstand the neoplastic effects of chemical carcinogens in vitamin A deficiency.
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PMID:Effect of vitamin A deficiency on hepatic and intestinal drug metabolizing enzymes in rats. 250 73

Rat hepatic microsomal mixed-function oxidase activities were not significantly affected by vitamin A deficiency. Similarly cytosolic glutathione S-transferase and glutathione reductase activities as well as total glutathione levels were unaffected by the vitamin A status. Induction of the mixed-function oxidases by 3-methylcholanthrene or phenobarbitone was independent of the vitamin A status. No significant differences in microsomal chemiluminescence, before and following challenge with tertiary butyl hydroperoxide, were evident between the vitamin-A-deficient animals and those maintained on vitamin-A-supplemented diets. The present findings indicate that the protective action of vitamin A against chemical carcinogens is unlikely to involve modulation of the enzyme systems responsible for their metabolism.
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PMID:Effect of vitamin A on rat hepatic mixed-function oxidases, glutathione transferase activity and generations of oxygen radicals. 321 38

Vitamin A deficiency causes a significant decrease in superoxide dismutase, glutathione peroxidase and GSH levels. Simultaneously, it causes a marked increase in Phase I microsomal oxidation (cytochrome P-450, aniline hydroxylase, PNA-O-demethylase) as well as in enzymatic and non-enzymatic lipid peroxidation in lung. Among Phase II enzymes, cytosolic chlorodinitrobenzene glutathione-S-transferase (CDNB-GST) activity showed a significant increase whereas microsomal UDP-glucuronyl transferase and cytosolic p-nitrobenzoyl chloride- and dichloro nitrobenzyl chloride-S-transferase activities showed variable decrease reflecting an imbalance in the Phase I and Phase II enzyme systems. CDNB-GST and non-Se-GSH-Px, registered a parallel rise with pulmonary cytochrome P-450, aniline hydroxylase and O-demethylase, as an adaptive response to elevated Phase I enzyme activity.
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PMID:Effect of vitamin A deficiency on pulmonary defense systems of guinea pig lung. 324 89

The metabolism of (3H)-benzo(a)pyrene and the activities of enzymes involved in its metabolism were studied in rat lung and liver in vitamin A deficiency. Deficiency of vitamin A resulted a significant decrease in the overall metabolism of benzo(a)pyrene in the liver in vitro, whereas no significant difference was evident in the lung. The ethyl acetate-soluble metabolites of benzo(a)pyrene formed by lung and liver preparations were unaltered qualitatively by vitamin A deficiency. However, quantitative analysis revealed that vitamin A deficiency decreased the yield of dihydrodiols, quinones and phenols in liver, and dihydrodiols in lung. The hepatic cytochrome P-450 content, arylhydrocarbon hydroxylase and uridine diphosphate-glucuronosyl transferase activities were reduced, whereas glutathione S-transferase activity was increased in the vitamin A deficient animals. Contrary to this, pulmonary cytochrome P-450 content was above the control values (p less than 0.01) and no alteration in pulmonary arylhydrocarbon hydroxylase activity was observed in vitamin A deficient rats. Uridine diphosphate-glucuronosyltransferase and glutathione S-transferase activities were impaired in lung by inducing vitamin A deficiency. However, no significant difference was evident in the overall metabolism of benzo(a)pyrene by lung supernatants from the two groups.
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PMID:Effect of vitamin A deficiency on pulmonary and hepatic in vitro metabolism of benzo(a)pyrene in rat. 393 30

The effect of intratracheal instillation of different doses of benzo(a)pyrene (0.1, 1.0 and 2.0 mg) on the drug metabolizing enzymes of lung and liver was analysed in rats fed diet with or without vitamin A for 5-6 weeks. Benzo(a)pyrene exposure at 2.0 mg dose only elevated the level of cytochrome P-450 and b5, and activity of benzopyrene hydroxylase in liver, and extent of increase was similar in normal and vitamin A deficient groups. Contrary to this, pulmonary contents of cytochrome P-450 and b5, and benzopyrene hydroxylase activity increased over control values in both the groups even at lower doses of benzo(a)pyrene. Moreover, their values were higher in vitamin A deficient-treated groups compared to normal-treated controls. Increase in these parameters was greater in lung as compared to increase in liver. NADPH cytochrome C-reductase in lung and liver was not affected either by inducing vitamin A deficiency or exposing these rats further to benzo(a)pyrene. Uridine-diphospho-glucuronosyl-transferase (UDP-GT) activity in normal and vitamin A deficient groups was enhanced following exposure to benzo(a)pyrene both in lung and liver. However, activity of this enzyme remained impaired in vitamin A deficient groups, benzo(a)pyrene exposed or not exposed when compared to respective normal controls. Glutathione S-transferase activity remained unchanged following exposure to benzo(a)pyrene both in lung and liver. The apparent increase in hepatic glutathione S-transferase and decrease in pulmonary glutathione S-transferase activity in vitamin A deficiency was only due to vitamin A deficient status of rats with no further effect of benzo(a)pyrene.
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PMID:Effect of intratracheally instilled benzo(a)pyrene on the pulmonary and hepatic drug-metabolizing enzymes in normal and vitamin A deficient rats. 401 64

The effect of vitamin A status on colon and liver glutathione content and the activity of glutathione S-transferase was studied in rats. Animals were fed diets with or without vitamin A for 4-5 weeks. There was no difference in the weight gains of control and deficient animals. Hepatic and colonic level of vitamin A was significantly reduced in vitamin A deficient animals. Hepatic glutathione content was below control values (31%); whereas activity of glutathione S-transferase was enhanced in deficient animals (41.2%). Contrary to this, colon glutathione S-transferase activity was significantly reduced (40.7%) and glutathione content remained unchanged in vitamin A deficiency.
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PMID:Effect of vitamin A deficiency on the level of glutathione and glutathione S-transferase activity in rat colon and liver. 665 Mar

The temporal effects of vitamin A deficiency on hepatic cytochrome P-450-dependent and conjugation reactions were studied in the rat. Cytochrome P-450 levels and N-methyl-p-chloroaniline N-demethylase activity were significantly reduced in the deficient animals. No other changes in parameters dependent on cytochrome P-450 were observed in vitro. Decreases in hepatic cytochrome P-450 were accompanied by a prolongation in hexobarbital sleeping times in deficient animals. The p-aminobenzoic acid N-acetyltransferase activity was higher in the deficient animals at 8 weeks, but by 10 weeks the activity in fact was significantly lower as compared to controls. Activities of 'native' and UDP N-acetylglucosamine 'activated' UDP-glucuronyltransferase were reduced in vitamin A deficiency. In contrast to this general pattern of impaired drug metabolism in vitamin A deficiency, glutathione S-aryltransferase activity was markedly enhanced at all time points from 4 to 10 weeks. Activities of this enzyme were twice controls at 6 weeks, a time at which no other enzyme changes were observed.
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PMID:Hepatic cytochrome P-450-dependent metabolism and enzymatic conjugation of foreign compounds in vitamin A-deficient rats. 722 May 90

Feeding male weanling rats on a vitamin A-deficient diet for 6 weeks resulted in significant increases (44-57%) in glutathione S-aryl-, S-aralkyl- S-alkyl- and S-epoxidetransferase activities in the liver cytosol. Only the S-aralkyl- (27%) and S-alkyltransferase (14%) activities were significantly increased in the kidney as a result of deficiency. There was no effect on any of the pulmonary glutathione S-transferase activities. The increases in hepatic transferase activities were due primarily to increases (25-96%) in the apparent Vmax. There were no changes in the apparant Km of any of the four drug substrates employed. With 3,4-dichloronitrobenzene as the second substrate, the apparent Km for glutathione was increased by over 2-fold in vitamin A-deficient livers as compared with controls. The relationship between these results and enhanced susceptibility to chemical carcinogens in vitamin A deficiency is briefly discussed, and comparison is made between the effects of this nutritional state and pretreatment with drug inducers on the glutathione S-transferases.
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PMID:The effect of vitamin A deficiency on hepatic, renal and pulmonary glutathione S-transferase activities in the rat. 747 42


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