Induction by kopsinine of hepatic mixed-function oxidase in mice

Kopsinine is an indole alkaloid. Oral administration of kopsinine 200 mg/kg once daily for 3 d significantly increased liver microsomal protein, cytochrome P-450, cytochrome b5, NADPH-cytochrome C reductase, aminopyrine demethylase and benzo(a)pyrine hydroxylase activities in mice. kopsinine only induced cytochrome P-450 in rough endoplasmic reticulum of liver. SDS-polyamine gel electrophoresis analysis showed that the protein bands of microsomes from kopsinine treated mice were similar to that induced by phenobarbital in mice. Metyrapon, a specific inhibitor of cytochrome P-450, partially antagonized aminopyrine demethylase activity of microsomes from mice treated with kopsinine. The results suggest that kopsinine yields a pentobarbital-like induction on liver mixed function oxidase in mice. In addition, kopsinine was found to shorten the barbital-induced sleeping time in mice.