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

Arylhydrocarbon-hydroxylase (AHH) is a cytochrome P-450-dependent polysubstrate mono-oxygenase 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. We suggest that 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.