Comparison of covalent binding of acetaminophen and the regioisomer 3'-hydroxyacetanilide to mouse liver protein.

摘要: Abstract The hepatotoxicity of the analgesic acetaminophen has been previously attributed to metabolic activation by cytochrome P450 reactive intermediate N-acetyl-p-benzoquinone imine. At therapeutic doses this species is detoxified reaction with glutathione; however, following a hepatotoxic dose, liver glutathione levels are depleted and metabolite covalently binds primarily cysteine groups on proteins as 3-(cystein-S-yl)acetaminophen adducts. Altered function critical postulated be mechanism hepatotoxicity. Covalent binding studied both radiochemical methods immunochemical methods. Utilizing Western blot analysis an antiserum which recognizes we have shown that covalent occurs number in various hepatic fractions. In effort better understand role toxicity, others non-hepatotoxic isomer 3′-hydroxyacetanilide. Administration large radiolabeled or 3′-hydroxyacetanilide resulted similar proteins. To toxicity administered mice acetaminophen, analyzed fractions for protein adducts using anti-3-(cystein-5-yl)acetaminophen anti-arylacetamide antisera assays. Analysis from acetaminophen-treated mice, showed, reported, 3′-hydroxyacetanilide-treated were detected only. A major adduct was observed microsomes at 50 kDa. Minor 47 kDa 56 cytosol. 3′-Hydroxyacetanilide not 10 000 × g pellet. Densitometric time course indicated peak microsomal occurred 1 h subsequently decreased.