Metabolism of benzo[a]pyrene in isolated human scalp hair follicles.

Human scalp hair follicles contain an enzyme system that metabolizes the carcinogen benzo[a]pyrene. The major ethyl acetate soluble metabolites are 7,8-dihydro-7,8-dihydroxybenzo[a]pyrene,9,10-dihydro-9,10-dihydroxybenzo[a]pyrene and 3-hydroxybenzo[a]pyrene. Addition of 1,1,1-trichloropropene-2,3-oxide (TCPO), an inhibitor of epoxide hydratase, prevents the formation of the dihydrodiols. The overall metabolism can be inhibited by the addition of alpha-naphthoflavone. The metabolism of benzo[a]pyrene in a cell culture of human scalp hair follicles has also been investigated. The results show that the activity of arylhydrocarbon hydroxylase (AHH) and epoxide hydratase (EH) is maintained in culture.