Glutathione S-transferase Activity In Liver Research Articles

A comparison of the subcellular distribution, subunit composition and bile acid-binding activity of glutathione S-transferases from trout and rat liver

1. 1. More than 90% of the glutathione S-transferase activity in both trout and rat liver is in cytosol. The activity in the microsomal fraction of rat but not trout liver is stimulated by iodoacetamide. 2. 2. The trout liver enzymes are dimers. The molecular weights of their monomers are similar to those of the Ya (22,000) and Yb (23,500) monomers of the rat liver enzymes. 3. 3. Unlike the enzymes from rat liver, those from trout liver do not bind glycocholate. 4. 4. Trout liver contains a species (15,000) that does bind glycocholate.

Glutathione S-transferase activities in rat liver: Effect of some factors influencing the metabolism of xenobiotics

The effect of some factors influencing the metabolism of xenobiotics on the glutathione content as well as the glutathione S-transferase activities towards 1-chloro-2,4-dinitrobenzene (aryl substrate) and 1,2-epoxy-3-(p-nitrophenoxy)propane (epoxide substrate) were studied in rat liver cytosol. Metabolic inducers (phenobarbital, rifampicin, DDT) as well as fasting led to marked increases in both glutathione transferase activities. Partial hepatectomy, acute and chronic alcohol pretreatment, experimental diabetes and thyroid dysfunction resulted in a more or less pronounced increase in the epoxide transferase activity whereas the aryl transferase remained unaffected. Experimental cholestasis and liver pre-injury following the administration of CCl4 decreased the glutathione S-transferase activity towards the epoxide substrate but not that towards the aryl substrate.

Assaying glutathione S-transferase activity in lung and liver with 3H-styrene oxide as substrate

Summary As with many radioactive assay methods, the sensitivity of published procedures for assaying glutathione S-transferase activity with 3 H-styrene oxide is limited by the background. The modifications described here for reducing this background increase the sensitivity of this assay so that it can easily be used with preparations containing low activity, such as the supernatant fraction from rat lung. Glutathione S-styrene oxide transferase activity is not catalyzed by a single enzyme, but rather by several (if not all) of the glutathione S-transferases. This activity is not inhibited by concentrations of 1,1,1-trichloropropene 2,3-oxide or cyclohexene oxide which totally inhibit epoxide hydratase.

Inhibition of rat liver glutathione S‐transferase activity by aprotic solvents

FEBS LettersVolume 101, Issue 1 p. 187-190 Full-length articleFree Access Inhibition of rat liver glutathione S-transferase activity by aprotic solvents First published: May 01, 1979 https://doi.org/10.1016/0014-5793(79)81323-XCitations: 13AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume101, Issue1May 01, 1979Pages 187-190 ReferencesRelatedInformation

Levels of glutathione, glutathione reductase and glutathione S-transferase activities in rat lung and liver

Levels of glutathione, glutathione reductase and glutathione S-transferase activities in rat lung and liver have been investigated. After perfusing the lung to remove contaminating blood, this organ was found to have an apparent concentration of glutathione (2 mM) which is approx. 20% of that found in the liver. Both organs contain very low levels of glutathione disulfide. Neither phenobarbital nor methylcholanthrene had a significant effect on the levels of reduced glutathione in the lung and liver. In addition, the activities of some glutathine-metabolizing enzymes — glutathione reductase and glutathione S-transferase activity assayed with four different substances — were observed to be 5- to 60-fold lower in lung tissue than in the liver.

Glutathione peroxidase activities from rat liver

There are two enzymes in rat liver with glutathione peroxidase activity when cumene hydroperoxide is used as substrate. One is the selenium-requiring glutathione peroxidase (glutathione:hydrogen-peroxide oxidoreductase, EC 1.11.1.9) and the other appears to be independent of dietary selenium. Activities of the two enzymes very greatly among tissues and among animals. The molecular weight of the enzyme with selenium-independent glutathione peroxidase activity was estimated by gel filtration to be 35 000, and the subunit molecular weight was estimated by dodecyl sulfate-polyacrylamide gel electrophoresis to be 17 000, Double reciprocal plots of enzyme activity as a function of substrate concentration produced intersecting lines which are suggestive of a sequential reaction mechanism. The K m for glutathione was 0.20 mM and the K m for cumene hydroperoxide was 0.57 mM. The enzyme was inhibited by N-ethylmaleimide, but not by iodoacetic acid. Inhibition by cyanide was competitive with respect to glutathione and the K i for cyanide was 0.95 mM. This selenium-independent glutathione peroxidase also catalyzes the conjugation of glutathione to 1-chloro-2,4-dinitrobenzene. Along with other similarities to glutathione S-transferase, this suggests that the selenium-independent glutathione peroxidase and glutathione S-transferase activities in rat liver are of the same enzyme.

Hepatic and extrahepatic metabolism of 14 C-styrene oxide

With 8-(14)C-styrene oxide as substrate, specific glutathione S-transferase and epoxide hydrase activities were determined in subcellular fractions of liver, lungs, kidney, and intestinal mucosa from rabbit, rat, and guinea pig. Liver had the highest enzyme activities in each species. Rat and guinea pig had higher glutathione S-transferase activity in both liver and kidney than rabbit. Rat testis also had appreciable glutathione S-transferase activity. The perinatal development of epoxide hydrase and glutathione S-transferase was followed in liver and several extrahepatic tissues of fetal and neonatal guinea pigs and rabbits. The rates at which enzyme activities reached adult levels in the extrahepatic tissues differed from the liver in both species. Epoxide hydrase and glutathione S-transferases developed at different rates in each organ, demonstrating that the relative importance of these two detoxifying pathways for styrene oxide may shift before and after birth. The effects of pretreating male and female rats with phenobarbital (PB), 1,2,3,4-dibenzanthracene (DBA), pregnenolone-16alpha-carbonitrile (PCN), or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on hepatic and extrahepatic epoxide hydrase and glutathione S-transferase activities toward styrene oxide were determined. PB increased both enzyme activities in liver of both sexes. PCN induced only glutathione S-transferase activity in female liver. Extrahepatic epoxide hydrase and glutathione S-transferase activities were unaffected except that TCDD doubled female renal epoxide hydrase activity and PB increased intestinal epoxide hydrase activity in both sexes. Styrene oxide biotransformation was studied in isolated, perfused rat liver and rabbit lung preparations. Conjugation with glutathione was a major metabolic pathway although significant amounts of diol were also formed in each instance. In rat liver, 27-40% of the administered styrene oxide was excreted via the bile mainly as S-(1-phenyl-2-hydroxyethyl)glutathione.