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)

The effect of fly ash inhalation on xenobiotic metabolizing enzymes and heme metabolism in lung and liver has been studied in rats. Fly ash inhalation induced pulmonary and hepatic cytochrome P-450 content, aryl hydrocarbon hydroxylase and glutathione S-transferase activity. Induction of cytochrome P-450 was accompanied by induction of delta-amino levulinic acid synthetase in lung and inhibition of heme oxygenase in both lung and liver. Fly ash inhalation induced those species of cytochrome P-450 which closely resembled cytochrome P-448 in spectral properties and electrophoretic mobility.
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PMID:Induction of pulmonary and hepatic cytochrome P-450 species by coal fly ash inhalation in rats. 272 10

Testicular toxicants have become of increasing importance necessitating a better understanding of the possible role of testicular xenobiotic metabolism. The responsiveness of testicular microsomal epoxide hydrolase (mEH), cytosolic epoxide hydrolase (cEH), and cytosolic glutathione S-transferase (cGST) to hepatic inducers was studied in sexually mature male F344 rats and CD-1 mice. The hepatic inducers employed were phenobarbital (PB), beta-naphthoflavone (BNF), and butylated hydroxyanisole (BHA) which are known to induce cytochrome P-450, cytochrome P-448, and cGST, respectively. Hepatic mEH, cEH and cGST activities were assessed as positive controls. Measurable activities of all enzymes studied were present in the testes of both rats and mice. PB, BNF, and BHA produced the expected effects on mEH, cEH, and cGST in rat and mouse livers, whereas the testes were generally nonresponsive to the inducers. Induction of testicular cGST by PB occurred in mice but not rats and was the only testicular effect produced by the hepatic inducers in this study.
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PMID:Effects of hepatic inducers on testicular epoxide-metabolizing enzymes in the rat and mouse. 273 60

Adult male Fischer 344 rats were fed inadequate, adequate, and excessive quantities of dietary protein (8, 12, and 22%, respectively) for a period of 14 days. An increase in dietary protein did not increase liver weight but resulted in an increase in cytochrome P-450 content and 7-ethoxycoumarin O-deethylase activity. No significant difference in glutathione S-transferase activity was observed at the three protein levels. The in vivo hepatotoxicity of bromobenzene increased with an elevation in dietary protein intake from 12 to 22%. These data from mature rats follow trends similar to findings we have reported previously with juvenile rats.
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PMID:Sensitivity of selected drug biotransformation enzymes to dietary protein levels in adult F344 male rats. 276 99

1. The effects of dietary clofibrate (0.5%, w/w, for 10 days) on seven inbred strains of mice--C57BL/6, C57BL/B10A(5R), ATL/OLA, C3H/HE/OLA, BALB/C, CBA/CA and A/J/OLA--and three strains of rats--Sprague-Dawley, Wistar and LOU/OLA--have been investigated. Liver weight, peroxisome proliferation, catalase activity, cytosolic, microsomal and mitochondrial epoxide hydrolase activities, cytochrome oxidase activity, microsomal cytochrome P-450 content and cytosolic glutathione transferase activity in liver were determined, together with cytosolic and microsomal epoxide hydrolase and cytosolic glutathione transferase activities in the kidneys. 2. In all cases peroxisome proliferation and induction of cytosolic epoxide hydrolase were observed in livers of rodents exposed to clofibrate. Thus, no non-responsive strains were found and further evidence for a coupling between these two phenomena was provided. In many cases significant increases in the liver microsomal cytochrome P-450 content and decreases in the hepatic cytosolic glutathione transferase activity were also seen. 3. High levels of cytosolic epoxide hydrolase were found in the rat kidney. In several strains of mice and rats renal cytosolic epoxide hydrolase activity was increased by clofibrate. 4. There were often considerable strain differences. However, in general mice had higher cytosolic epoxide hydrolase and glutathione transferase activities, whereas rats had higher microsomal epoxide hydrolase activities.
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PMID:Proliferation of peroxisomes and induction of cytosolic and microsomal epoxide hydrolases in different strains of mice and rats after dietary treatment with clofibrate. 281 29

Hepatic biotransformation was studied in microsomal (cytochrome P-450-dependent monooxygenase activities) and cytosolic (glutathione S-transferase activities) fractions from Japanese quail (Coturnix coturnix) and buzzard (Buteo buteo). Monooxygenase activities were not very different apart from a high 7-ethoxycoumarin de-ethylase activity in quail as compared to buzzard. Glutathione S-transferase activities were higher in quail than in buzzard. DP5 (a commercial mixture of PCBs containing 50% chlorine) produced a marked increase in monooxygenase activity from quail liver. In contrast, no induction was found in buzzard under the same conditions. Glutathione S-transferase activities were not modified in both species.
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PMID:Hepatic biotransformation in the buzzard (Buteo buteo) and the Japanese quail (Coturnix coturnix): effect of PCBs. 286 18

The purpose of this investigation was to determine the effects of a subclinical fascioliasis at various stages of its development (by week--4, 8, 12, and 16 weeks after the infestation by an oral administration of 150 metacercariae of Fasciola hepatica) on the activity of some hepatic drug-metabolizing systems in lamb. The parasitic pathology was ascertained at autopsy and by clinical observation of animals. Hepatic microsomal cytochrome P-450 content was significantly decreased (by 9-22%) in all infected groups of animals. In early stages of the parasitic disease, decreases in cytochrome b5 content (10-18%) and ethoxycoumarin O-deethylase (25%) were observed, whereas aminopyrine N-demethylase, benzphetamine N-demethylase, and aniline hydroxylase were significantly lowered by 8 to 16 weeks postinfection. Among investigated transferases, glutathione transferase was only decreased (28%) in animals killed 16 weeks after the infestation; in these animals a significant increase in microsomal gamma-glutamyltransferase was observed, probably related to the elevated plasma activity of this enzyme. By 8 weeks postinfection, a simultaneous increase in cytosolic calcium (38%) and decrease in cytosolic glutathione (22%) would correspond to an oxidative cell injury occurring in the course of fascioliasis. The consequences of the fascioliasis-induced decreases in liver-oxidative and conjugative liver drug metabolism are discussed.
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PMID:Incidence of experimental fascioliasis on the activity of drug-metabolizing enzymes in lamb liver. 286 58

Plaice were treated with an acute dose of a polyaromatic hydrocarbon (3-methylcholanthrene, 3-MC) or cadmium, or 3-MC and cadmium by i.p. injection. The effects on hepatic detoxication systems, cytochrome P-450 (ethoxyresorufin O-deethylase, EROD), UDP-glucuronyl transferase, glutathione S-transferase, glutathione peroxidase activities, total glutathione (GSH), metallothionein and Cd and Zn in the cytosol were studied over a 14 day period. 3-MC increased EROD (7-18-fold), glucuronyl transferase (40%) and GSH transferase (200%) activities, whereas GSH peroxidase activity decreased by 60%. Cd treatment inhibited EROD (90%), GSH transferase (90%) and GSH peroxidase (30%) activities and displaced Zn. Total GSH levels increased (200%) prior to onset of metallothionein synthesis (6 days). Cotreatment with 3-MC and Cd led to a marked increase in GSH levels (300%) but the onset of metallothionein synthesis was delayed by a week. Induction of enzyme activities was abolished, EROD activity was strongly inhibited and there was a transient 50-90% decrease in glucuronyl transferase, GSH transferase and GSH peroxidase activities on days 2 and 3 after treatment. The results indicate that a polyaromatic hydrocarbon could result in increased peroxidative damage, the heavy metal Cd can severely inhibit organic xeno- and endobiotic metabolism and that the effects of both agents may be synergistic.
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PMID:The time course of effects of cadmium and 3-methylcholanthrene on activities of enzymes of xenobiotic metabolism and metallothionein levels in the plaice, Pleuronectes platessa. 286 5

4-Monomethylaminoantipyrine (MAA)-induced increase of hepatic drug metabolizing enzymes was suppressed by SKF 525-A. This may be due to the partial binding of SKF 525-A to a portion of cytochrome P-450. On the other hand, glutathione S-transferase and gamma-glutamyltranspeptidase (gamma-GTP) activities of rat liver were both induced by repeated administration of MAA in combination with SKF 525-A. In addition, under the same condition, glutathione level in rat liver was significantly decreased.
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PMID:Effects of co-administration of monomethylaminoantipyrine with diethylaminoethyl 2,2-diphenylvalerate (SKF 525-A) on gamma-glutamyltranspeptidase, glutathione S-transferase and hepatic drug metabolizing enzyme activities in rats. 287 6

When mice were exposed to 1% 2-ethylhexanoic acid in the diet, cytosolic and microsomal epoxide hydrolase (EC 3.3.2.3) activities were increased maximally (2-2.5- and 0.5-1-fold, respectively) after 3 days. Immunochemical quantitation of these enzymes indicated that the process involved was a true induction in both cases. Maximal levels of peroxisome proliferation (as indicated by carnitine acetyltransferase activity) were obtained after 7 days of exposure. All three of these activities returned to control levels within 4 days after termination of the treatment. The liver somatic index was slightly increased after 4 days of administration of 1% 2-ethylhexanoic acid, but the protein contents of the "mitochondrial," microsomal, and cytosolic fractions were unaffected. The activity of peroxisomal palmitoyl-CoA beta-oxidation was increased 2-fold, whereas peroxisomal catalase activity was unaffected. Exposure to 2-ethylhexanoic acid also increased cytochrome oxidase activity, suggesting an effect on mitochondria. Other parameters of detoxication--i.e. total microsomal cytochrome P-450 content, cytosolic glutathione transferase activity toward 1-chloro-2,4-dinitrobenzene, and the "cytosolic" epoxide hydrolase activity localized in the "mitochondrial" fraction--were not affected by 4 days of treatment with 1% 2-ethylhexanoic acid.
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PMID:Characterization of the induction of cytosolic and microsomal epoxide hydrolases by 2-ethylhexanoic acid in mouse liver. 288 46

Biochemical phenotypes such as the forms of enzyme proteins alter during the promotion and progression stages in chemical hepatocarcinogenesis. Many enzymes or isoenzymes have been identified as markers of (pre) neoplastic hepatic tissues and used for analysis of the carcinogenic process. The levels of hepatic isoenzymes decrease and those of prototypic or fetal isozymes increase during the progression of hepatocarcinogenesis. Some drug-metabolizing enzymes are also very variable at the promotion stage in rat chemical carcinogenesis; Phase I enzymes such as cytochrome P-450 decrease and Phase II (iso)-enzymes such as UDP-glucuronyl-transferase, glutathione S-transferase (GST) and gamma-glutamyl transpeptidase (gamma-GTP) increase. A new neutral GST form with pI 7.0 (GST-P) has been identified by us as one of the best markers for rat chemical hepatocarcinogenesis. GST-P is a homodimer consisting of a subunit (Mr 26,000, more accurately 23,307, and pI 6.7), the smallest among rat GST subunits, and differs immunochemically from any other GST form. It is present in very low levels in normal rat liver and is not inducible by most drugs including carcinogens without the appearance of preneoplastic hepatocyte nodules (HN) but it is increased by several ten-fold in HN-bearing liver and hepatomas induced by different carcinogens. Immunohistochemically, it is localized in HN and very early and small GST-positive foci are detectable using anti-GST-P antibody. (Pre) neoplastic hepatic lesions induced by nongenotoxic carcinogens such as hypolipidemic peroxisome-proliferating agents do not express GST-P as well as gamma-GTP.
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PMID:[Enzyme alterations during chemical hepatocarcinogenesis]. 288 6


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