Differential effect of several inducers on hepatic and mammary benzo(A)pyrene metabolism in rat and hamster.

Rat and hamster mammary gland, in comparison with the liver, were examined for their in vitro ability to metabolize polycyclic aromatic hydrocarbons, and for the effects of pretreatment with various mixed function oxidase inducers on this metabolism. Hamster mammary microsomal benzo(a)pyrene (BP) hydroxylase activity was 4-fold greater than that in the rat, and this activity was induced 3- to 5-fold in the hamster, and 7- to 13-fold in the rat, by pretreatment with 7,12-dimethylbenz(a)anthracene, beta-naphthoflavone, Aroclor 1254 or 3-methylcholanthrene. Hamster hepatic microsomal BP-hydroxylase activity was 80-fold greater than in the rat. Whereas pretreatment with these enzyme inducers enhanced rat hepatic activity by 20- to 30-fold, little effect of "inducers" was observed on the hamster hepatic enzyme, even when the formation of the various BP metabolites was determined by high pressure liquid chromatography.