Induction of microsomal drug-metabolizing enzymes caused by hexobarbital

Summary Hexobarbital was given to anaesthetized mice for a period of 7 h by repeated i. p. injection, first of 100 mg/ kg, then several times of 50 mg/kg. A high level of hexobarbital was maintained in the liver. The activity of microsomal drug-metabolizing enzymes was induced by this treatment with hexobarbital. 30 min after a single i. p. injection of 100 mg/kg of hexobarbital, there was a significant inhibition of aminopyrine N-demethylase but none of cytochrome c and neotetrazolium reductases.—Hexobarbital in vitro inhibits aminopyrine N-demethylase but not cytochrome c reductase.