Transformation of normal hamster cells by benzo(a)pyrene diol‐epoxide

Abstract

The frequency of cell transformation was determined after treatment of normal hamster embryo cells with benzo(a)pyrene (BP) and six of its metabolites. These metabolites included the trans 4,5‐, 7,8‐ and 9,10‐dihydrodiols; the 4,5‐epoxide; and two stereoisomers of the non‐K‐region diol epoxides r‐7, t‐8‐dihydroxy t‐9, 10‐oxy‐7,8,9,10‐tetrahydro‐benzo(a)pyrene (diol‐epoxide I) and r‐7, t‐8, dihydroxy c‐9, 10‐oxy‐7,8,9,10‐tetrahydrobenzo(a) pyrene (diol‐epoxide II). The trans 7,8‐dihydrodiol was more active than the other two dihydrodiols tested and was also more active than the parent hydrocarbon BP. Of the three epoxides tested, the diol‐epoxide I was more active than the 4,5‐epoxide and diol‐epoxide II. The results suggest that diol‐epoxide I is a major cell‐transforming metabolite of BP.