Metabolism of papaverine. III. Effect of phenobarbital, 3-methylcholanthrene and SKF 525-A pre-treated in vivo and in vitro.
1. The metabolism of papaverine was studied in vitro using the 9000 g fraction of rat liver. Apparent Km and Vmax values were 1.6 X 10-5 M and 34 nmol/g/min. Three monodemethylated metabolites were found by t.l.c. 2. Pre-treatment of rats with phenobarbital enhanced the activity of papaverine O-demethylase, whereas pre-treatment with 3-methylcholanthrene did not. Pre-treatment with SKF 525-A, or addition of AKF 525-A invitro markedly inhibited the enzyme. 3. Pre-treatment of the rats with phenobarbital enhanced the biliary elimination rate of papaverine metabolites, whereas SKF 525-A pre-treatment slowed this elimination.
D000633:Aminopyrine N-Demethylase / Q000378:metabolism; D000818:Animals; D001646:Bile / Q000378:metabolism; D002855:Chromatography, Thin Layer; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D007274:Injections, Intraperitoneal; D007275:Injections, Intravenous; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology*; D009929:Organ Size / Q000187:drug effects; D010090:Oxidoreductases, O-Demethylating / Q000378:metabolism; D010208:Papaverine / Q000031:analogs & derivatives / Q000378:metabolism*; D010634:Phenobarbital / Q000494:pharmacology*; D011335:Proadifen / Q000494:pharmacology*; D051381:Rats
D008748:Methylcholanthrene; D003577:Cytochrome P-450 Enzyme System; D011335:Proadifen; D010208:Papaverine; D010090:Oxidoreductases, O-Demethylating; D000633:Aminopyrine N-Demethylase; D010634:Phenobarbital