Benzo(a)pyrene metabolism in mouse epidermis. Analysis by high pressure liquid chromatography and DNA binding.

Mouse epidermal homogenates contain an inducible aryl hydrocarbon hydroxylase (AHH) complex that catalyzes the formation of benzo(a)pyrene-7,8-dihydrodiol from benzo(a)pyrene (BP) as assessed by high pressure liquid chromatography (HPLC). 5,6-Benzoflavone (5,6-BF), 7,8-benzoflavone (7,8-BF) and 17-beta-estradiol decreased and butylated hydroxytoluene (BHT) enhanced oxidative metabolism of BP when added in vitro. Epoxide hydrase activity (hydration of benzo(a)pyrene-4,5-epoxide) (BP-4,5-epoxide) was enhanced by 17-beta-estradiol, 5,6-BF, and 7,8-BF. BHT exhibited no significant effect and 1,2-epoxy-3,3,3-trichloropropane (TCPO) inhibited hydrase activity. The capacity of epidermal homogenates to catalyze the covalent binding of BP to DNA indicated that addition of both 5,6-BF and 7,8-BF decreased binding. BHT and TCPO did not significantly affect DNA-binding.