Differential induction of cytochrome P-450 isozymes by rifampicin in the Chinese hamster, Cricetus griseus.

Treatment of male and female Chinese hamsters with rifampicin at intraperitoneal doses of 25 and 50 mg/kg did not increase the cytochrome P-450 content of the liver except for a 1.3-fold increase in male hamsters at a dose of 50 mg/kg. Enhancement of the activities of erythromycin N-demethylase and testosterone hydroxylases, except for 15 alpha-hydroxylation, was observed in the livers of both male and female hamsters treated with rifampicin at both doses. Western blot analysis revealed that rifampicin caused no change in the content of CYP3A subfamily proteins in the liver, whereas changes in that of CYP2A subfamily proteins were evident.