Abstract

Hepatic microsomal drug metabolizing enzyme activity and hepatic ultrastructure have been studies in rats treated with phenobarbital, chlordane, benzpyrene, or methylcholanthrene. These studies have allowed a classification of these stimulators of drug metabolism into groups: phenobarbital and chlordane vs. benzpyrene and methylecholanthrene. Phenobarbital and chlordane stimulate a variety of microsomal drug metabolisms and also appear to cause a marked proliferation of smooth-surfaced endoplasmic reticulum (SER) in the hepatic cell. Benzpyrene and methylcholanthrene stimulate only a few microsomal drug metabolizing enzymes and do not appear to cause any pronounced increase in hepatic cell SER.