2-Butanol metabolism by rat hepatic and pulmonary cytochromes P450

Three microsomal enzyme inducers, ethanol, phenobarbital (PB), and beta-naphthoflavone (beta NF), were compared for their effects on butanol oxidase activity in rat hepatic and pulmonary microsomes. Four concentrations of 2-butanol (1.0, 5.0, 10, and 33 mM) were used to determine if the effects of induction on 2-butanol metabolism were substrate concentration dependent. Ethanol induced at all substrate concentrations in the liver while PB induced at only the high substrate concentrations (5.0, 10, and 33 mM). beta NF did not induce at any substrate concentration. 2-Butanol oxidation in the lung was not induced by any of the treatments. Thus, both ethanol and phenobarbital induce hepatic enzymes capable of 2-butanol oxidation, and the isozyme(s) induced by the latter has a somewhat lesser affinity for this alcohol.