RT Journal Article SR Electronic T1 p-Nitrophenol hydroxylation. A microsomal oxidation which is highly inducible by ethanol. JF Drug Metabolism and Disposition JO Drug Metab Dispos FD American Society for Pharmacology and Experimental Therapeutics SP 548 OP 552 VO 13 IS 5 A1 L A Reinke A1 M J Moyer YR 1985 UL http://dmd.aspetjournals.org/content/13/5/548.abstract AB 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.