title: Heterogeneity of hepatic nicotine oxidase.
abstract: When rats were pretreated with 3-methylcholanthrene of beta-naphthoflavone, hepatic nicotine oxidase activity per cytochrome P-448 molecule decreased, but the specific activity of the enzyme remained unchanged. After phenobarbital pretreatment, the specific activity of nicotine oxidase increased while the activity of the enzyme per cytochrome P-450 molecule decreased. alpha-Naphthoflavone selectively inhibited the activities of phenobarbital-induced nicotine oxidase and constitutive form(s) of the enzyme. These results show that phenobarbital-induced cytochrome P-450 and constitutive form(s) of the enzyme may be active in hepatic nicotine oxidation.
mesh_terms: D000818:Animals; D001571:Benzoflavones / Q000494:pharmacology; D019388:Cytochrome P-450 CYP1A2; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D003580:Cytochromes / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology; D010088:Oxidoreductases / Q000378:metabolism*; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D019324:beta-Naphthoflavone
chemical_list: D001571:Benzoflavones; D003580:Cytochromes; D007527:Isoenzymes; D008748:Methylcholanthrene; D019324:beta-Naphthoflavone; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; C017170:Cyp1a2 protein, rat; D019388:Cytochrome P-450 CYP1A2; C034523:nicotine oxidase; D010634:Phenobarbital