Inducibility of arylhydrocarbon-hydroxylase activity in human hair follicles by topical application of liquor carbonis detergens (coal tar)

Abstract

Arylhydrocarbon-hydroxylase (AHH) is a cytochrome P-450-dependent polysubstrate monooxygenase which plays an important role in converting some compounds (e.g. benzo[a]pyrene) to highly reactive carcinogenic species. A simple AHH assay is described, using [3H]benzo[a]pyrene as substrate. 7,8-Benzoflavone (10-4 M) inhibits 92% of the measured enzyme activity. Liquor carbonis detergens (which contains coal tar) induces AHH activity in human hair follicles in vivo. Using this simple assay, hair follicles would be a very suitable tissue to test whether the AHH-controlling gene is of significance in producing cancer.