TY - JOUR T1 - ACETAMINOPHEN-INDUCED HEPATIC NECROSIS. III. CYTOCHROME P-450-MEDIATED COVALENT BINDING <em>IN VITRO</em> JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 203 LP - 210 VL - 187 IS - 1 AU - W. Z. Potter AU - D. C. Davis AU - J. R. Mitchell AU - D. J. Jollow AU - J. R. Gillette AU - B. B. Brodie Y1 - 1973/10/01 UR - http://jpet.aspetjournals.org/content/187/1/203.abstract N2 - The binding of 3H-acetaminophen to hepatic microsomes was studied in vitro. Binding of 3H-acetaminophen to rat and mouse microsomal protein was linear with time and with protein concentration. Binding occurred by covalent linkage to amino acids of protein. Reduced nicotinamide adenine dinueleotide phosphate and oxygen were necessary for the binding while carbon monoxide or cobaltous chloride pretreatment inhibited it, demonstrating that a cytochrome P-450-dependent. mixed function oxidase mediated the binding. The extent of in vitro binding correlated with treatments that alter hepatic necrosis and in vivo binding, indicating that in vitro binding was a valid index of acetaminophen-induced hepatotoxicity. Analogous studies with 2-acetylaminofluorene showed that its binding to microsomal protein also was dependent on cytochrome P-450. Since the toxicity of 2-acetylaminofluorene results from its conversion to an N-hydroxy derivative, the collective data are consistent with the hypothesis that the hepatotoxic metabolite of acetaminmophen may be an N-hydroxy derivative. © 1973 by The Williams &amp; Wilkins Company ER -