Activation of microsomal glutathione S-transferase in tert-butyl hydroperoxide-induced oxidative stress of isolated rat liver.
The activation of microsomal glutathione S-transferase in oxidative stress was investigated by perfusing isolated rat liver with 1 mM tert-butyl hydroperoxide (t-BuOOH). When the isolated liver was perfused with t-BuOOH for 7 min and 10 min, microsomal, but not cytosolic, glutathione S-transferase activity was increased 1.3-fold and 1.7-fold, respectively, with a concomitant decrease in glutathione content. A dimer protein of microsomal glutathione S-transferase was also detected in the t-BuOOH-perfused liver. The increased microsomal glutathione S-transferase activity after perfusion with t-BuOOH was reversed by dithiothreitol, and the dimer protein of the transferase was also abolished. When the rats were pretreated with the antioxidant alpha-tocopherol or the iron chelator deferoxamine, the increases in microsomal glutathione S-transferase activity and lipid peroxidation caused by t-BuOOH perfusion of the isolated liver was prevented. Furthermore, the activation of microsomal GSH S-transferase by t-BuOOH in vitro was also inhibited by incubation of microsomes with alpha-tocopherol or deferoxamine. Thus it was confirmed that liver microsomal glutathione S-transferase is activated in the oxidative stress caused by t-BuOOH via thiol oxidation of the enzyme.
Aniya
Y
Y
Laboratory of Physiology and Pharmacology, School of Health Sciences, Faculty of Medicine, University of the Ryukyus, Okinawa, Japan.
Daido
A
A
D000818:Animals; D003676:Deferoxamine / Q000494:pharmacology; D004229:Dithiothreitol / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D005033:Ethylmaleimide / Q000494:pharmacology; D005979:Glutathione Peroxidase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism*; D015151:Immunoblotting; D066298:In Vitro Techniques; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D016877:Oxidants / Q000494:pharmacology*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology*; D010545:Peroxides / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013438:Sulfhydryl Compounds / Q000378:metabolism; D014810:Vitamin E / Q000494:pharmacology; D020122:tert-Butylhydroperoxide
D016877:Oxidants; D010545:Peroxides; D013438:Sulfhydryl Compounds; D014810:Vitamin E; D020122:tert-Butylhydroperoxide; D005979:Glutathione Peroxidase; D005982:Glutathione Transferase; D003676:Deferoxamine; D005033:Ethylmaleimide; D004229:Dithiothreitol