TY - JOUR T1 - p-Nitrophenol hydroxylation. A microsomal oxidation which is highly inducible by ethanol. JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 548 LP - 552 VL - 13 IS - 5 AU - L A Reinke AU - M J Moyer Y1 - 1985/09/01 UR - http://dmd.aspetjournals.org/content/13/5/548.abstract N2 - p-Nitrophenol is widely employed as a substrate for the study of the glucuronide and sulfate conjugation pathways. However, in perfused livers from ethanol-treated rats, p-nitrophenol was rapidly metabolized to 4-nitrocatechol. The 4-nitrocatechol formed competed with p-nitrophenol for conjugation with glucuronic acid and sulfate, and interfered with the direct spectral measurement of p-nitrophenol. In isolated microsomes, rates of p-nitrophenol hydroxylation were increased 6-fold after chronic ethanol treatment. Much smaller induction was observed after pretreatment of rats with phenobarbital (70% increase) or beta-naphthoflavone (30% increase). In addition, the 6-fold increase in rates of p-nitrophenol hydroxylation after chronic ethanol treatment was greater than increases in activity observed for the microsomal metabolism of aniline, 7-ethoxycoumarin, benzo(a)pyrene, ethanol, or aminopyrine. These data demonstrate that p-nitrophenol may be an extremely useful substrate for the study of changes in drug-metabolizing activity induced by ethanol treatment. ER -