Studies on Microsomal Cytochrome P-450, Monooxygenases and Epoxide Hydrolase in Cultured Keratinocytes and Intact

Studies of drug and carcinogen metabolism in cultured keratin-ocytes and in intact epidermis from the skin of BALB/C mice were performed. The cultured cells were shown to retain 33 to 40 % of corresponding intact epidermal aryl hydrocarbon hy-droxylase (AHH), 7-ethoxycoumarin-O-de-ethylase (7-ED) and epoxide hydrolase activities. In vitro treatment of the cells or in vivo application to the skin of animals with the polycyclic aromatic hydrocarbons benz(a)anthracene (BA) or benzo-(a)pyrene resulted in significant induction of AHH and 7-ED activities. The responsiveness of AHH was greater than that of 7-ED in both preparations. BA (4 x 1 O M) induced AHH and 7-ED at least 1 2- and 4-fold, respectively, in either the keratin-ocytes or intact epidermis, whereas epoxide hydrolase activity was not altered in either preparation. All of these enzym