title: Differential inhibition of biphenyl hydroxylation in perfused rat liver.
abstract: A differential inhibition of biphenyl hydroxylation by alpha-naphthoflavone and metyrapone was observed in isolated perfused rat liver. alpha-Naphthoflavone inhibited 2- and 4-hydroxylation in livers from beta-naphthoflavone-pretreated animals but had no effect on both reactions in livers from phenobarbital-pretreated animals. Metyrapone inhibited 2- and 4-hydroxylation in phenobarbital-stimulated livers, but only insignificant inhibition of 2-hydroxylation and a slight enhancement of 4-hydroxylation by metyrapone was observed in beta-naphthoflavone-stimulated livers. Conjugation of 2-hydroxybiphenyl and 4-hydroxybiphenyl by isolated perfused livers was also studied. 4-Hydroxybiphenyl preferentially formed sulphates in livers from untreated animals but after induction glucuronidation was as effective as sulphation or even exceeded sulphation. Only glucuronic acid conjugates of 2-hydroxybiphenyl were detected.
mesh_terms: D000818:Animals; D001713:Biphenyl Compounds / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D003864:Depression, Chemical; D005419:Flavonoids / Q000494:pharmacology; D006900:Hydroxylation; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008797:Metyrapone / Q000494:pharmacology; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats; D013997:Time Factors
chemical_list: D001713:Biphenyl Compounds; D005419:Flavonoids; D003577:Cytochrome P-450 Enzyme System; D010634:Phenobarbital; D008797:Metyrapone