Induction of cytochromes P4502B1/2B2 by some antiepileptic drugs in rat liver.

The effects of phenobarbital (PB), carbamazepine (CBZ) and diazepam (DZ) on total hepatic cytochrome P450, cytochromes P4502B1/2B2 contents and aminopyrine N-demethylase activity was investigated. Adult male rats were treated per os with PB (80 mg/kg/day), CBZ (75 mg/kg/day) or DZ (90 mg/kg/day) for 3 consecutives days. Carbamazepine and phenobarbital produced significant increase of the contents of total cytochrome P450 and cytochromes P4502B1/2B2 as well as aminopyrine N-demethylase activity. In contrast, diazepam decreased the total hepatic cytochrome P450 content. This drug did not affect the level of cytochromes P4502B1/2B2 but increased aminopyrine N-demethylase activity comparing to the control animals.