Induction of hepatic CYP2B1/2 by a teratogenic compound cis-1-[-4-(p-menthane-8-yloxy)phenyl]piperadine (YM9429) in rats

A teratogenic compound cis-1-[-4-(p-menthane-8-yloxy)phenyl]piperadine (YM9429) selectively induces skeletal malformations characterized by cleft palate in rat fetuses. In the present study, we investigated the effect of YM9429 on hepatic cytochrome P-450s and their activities in rats. Oral administrations of YM9429 at a dose of 250, 500 or 750 mg/kg daily for 3 days induced cytochrome P-450 contents in a dose-dependent manner. Concomitant induction of enzyme activities of benzphetamine N-demethylase, erythromycin N-demethylase and, to a lesser extent, aminopyrine N-demethylase was observed. Immunoblot analysis revealed that YM9429 up-regulated hepatic levels of CYP2B1/2 and CYP3A1/2 proteins. A single dose of YM9429 at 250 mg/kg induced CYP2B1/2 protein levels significantly. These results suggest that YM9429 is a strong inducer of cytochrome P-450 with characteristics resembling those of phenobarbital.