Phenobarbital induction of procyclidine metabolism: in vitro study.

After pretreatment of adult male Wistar rats with phenobarbital, a well-known cytochrome P-450 inductor, the liver microsomal cytochrome P-450 content increased significantly compared to that of control rats. At the same time the amount of procyclidine, metabolized by the 9000 g supernatant fraction of rat liver homogenate fortified with a NADPH generating system, increased significantly as well. However when related to the liver microsomal cytochrome P-450 content, the amount of metabolized procyclidine does not differ anymore between phenobarbital treated and control rats. Therefore phenobarbital induces the in vitro metabolism of procyclidine.