Polychlorinated benzene and phenol congeners as inducers of rat hepatic drug-metabolizing enzymes in immature male Wistar rats.

Abstract

The effects of the higher chlorinated benzene and phenol congeners as inducers of the hepatic microsomal drug-metabolizing enzymes have been determined in the immature male Wistar rat by comparing the enzymic, electrophoretic, and spectral properties of the microsomes. 3,4,5-Trichlorophenol, 1,2,4,5-tetrachlorobenzene, 1,2,3,5-tetrachlorobenzene, 1,2,4-trichlorobenzene, and pentachlorobenzene induced 4-dimethylaminoantipyrine (DMAP) N-demethylase, an enzyme induced by phenobarbitone (PB) and several PB-type inducers. Hexachlorobenzene induced DMAP N-demethylase and aldrin epoxidase, two PB-inducible enzymes, and benzo[a]pyrene hydroxylase and ethoxyresorufin O-deethylase, two enzymes induced by 3-methylcholanthrene (MC). This mixed-type induction pattern has been previously reported for hexachlorobenzene. The remaining higher chlorinated benzene and phenol congeners were inactive as inducers of the drug-metabolizing enzymes in the immature male Wistar rats.