title: Role of iron and glutathione redox cycle in acetaminophen-induced cytotoxicity to cultured rat hepatocytes.
abstract: The aims of this study were to investigate the roles of iron as a catalyst in reactive oxygen metabolite-mediated cellular injury and of the endogenous antioxidant defenses against acetaminophen-induced cytotoxicity in cultured rat hepatocytes. Hepatocytes were isolated and cultured from either 3-methylcholanthrene-treated or untreated rats. Cytotoxicity was evaluated by measuring 51Cr and lactate dehydrogenase release. Acetaminophen caused dose-dependent cytotoxicity in 3-methylcholanthrene-treated, but not untreated, cells. There was a good correlation between 51Cr and lactate dehydrogenase release values. Pretreatment with both diethyl maleate, which covalently binds glutathione as catalyzed by glutathione-S-transferase, and bis(chloroethyl)-nitrosourea, an inhibitor of glutathione reductase, enhanced acetaminophen-induced cytotoxicity. Inhibition of endogenous catalase activity by pretreatment with aminotriazole did not affect acetaminophen-induced cellular damage. Addition of exogenous catalase failed to protect against acetaminophen-induced cytotoxicity. Preincubation with both deferoxamine, a ferric iron chelator, and phenanthroline, a ferrous iron chelator, diminished acetaminophen-induced cytotoxicity. These results indicate that iron is crucial in mediating acetaminophen-induced cytotoxicity and that the glutathione redox cycle, but not catalase, plays a critical role in the endogenous defenses against acetaminophen-induced cellular damage in cultured rat hepatocytes in vitro.
authors.affiliation: Department of Medicine, Veterans Affairs Medical Center, Long Beach, California 90822.
authors.forename: Y
authors.initials: Y
authors.lastname: Ito
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: H
authors.initials: H
authors.lastname: Ogonuki
authors.forename: H
authors.initials: H
authors.lastname: Hiraishi
authors.forename: M
authors.initials: M
authors.lastname: Razandi
authors.forename: A
authors.initials: A
authors.lastname: Terano
authors.forename: T
authors.initials: T
authors.lastname: Harada
authors.forename: K J
authors.initials: KJ
authors.lastname: Ivey
mesh_terms: D000082:Acetaminophen / Q000633:toxicity*; D000640:Amitrole / Q000494:pharmacology; D000818:Animals; D002330:Carmustine / Q000494:pharmacology; D002374:Catalase / Q000378:metabolism / Q000494:pharmacology; D002478:Cells, Cultured; D002860:Chromium Radioisotopes; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D003676:Deferoxamine / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism*; D005980:Glutathione Reductase / Q000037:antagonists & inhibitors / Q000378:metabolism; D007501:Iron / Q000502:physiology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000187:drug effects*; D008297:Male; D008298:Maleates / Q000494:pharmacology; D008748:Methylcholanthrene; D010084:Oxidation-Reduction; D010618:Phenanthrolines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D002860:Chromium Radioisotopes; D008298:Maleates; D010618:Phenanthrolines; D000082:Acetaminophen; D008748:Methylcholanthrene; D003577:Cytochrome P-450 Enzyme System; D007501:Iron; D007770:L-Lactate Dehydrogenase; D002374:Catalase; D005980:Glutathione Reductase; C014476:diethyl maleate; D005978:Glutathione; D003676:Deferoxamine; D002330:Carmustine; D000640:Amitrole