Effect of promethazine and isosafrole on rat-hepatic microsomal mono-oxygenase activity: comparison with classic inducers phenobarbitone and beta-naphthoflavone.

The characteristics of induction of rat-hepatic microsomal mono-oxygenase activity by promethazine and isosafrole have been investigated and compared with the classic inducers phenobarbitone and beta-naphthoflavone. Both promethazine and isosafrole pretreatments result in increased cytochromes P-450, and enhanced NADPH-cytochrome c reductase, aminopyrine N-demethylase, dichloronitroanisole O-demethylase, ethoxycoumarin O-deethylase and ethoxyresorufin O-deethylase activity. Isosafrole but not promethazine increased the liver to body weight ratio. It is concluded that promethazine and isosafrole pretreatment produces an induction of the rat-hepatic microsomal mono-oxygenase system which shows both phenobarbitone- and polycyclic aromatic hydrocarbon-type characteristics.