Metabolism of 7,12-dimethylbenz[a]anthracene in mouse skin homogenates analyzed with high-pressure liquid chromatography.

The metabolism of 7,12-dimethylbenz[a]anthracene (DMBA) in epidermal homogenates from 3-methylcholanthrene-pretreated mice was analyzed with high-pressure liquid chromatography. Metabolism was undetectable in the absence of pretreatment. Specific activities in epidermal homogenates from pretreated mice were found to be approximately 100 to 1000 times lower than those observed in comparable incubations containing hepatic microsomes from MC-pretreated rats. The major metabolite formed was identified as 7-hydroxymethyl-12-methylbenz[a]anthracene. Each of the known hydroxymethyl metabolites also was present in detectable quantities. The K-region diol was not measurably present in incubations with mouse skin homogenates or rat liver microsomes from MC-pretreated animals. 7,8-Benzoflavone, 5,6-benzoflavone, and 17-beta-estradiol were found to be potent inhibitors of the metabolic transformation of DMBA by epidermal homogenates in vitro, whereas butylated hydroxytoluene and 1,1,1-trichloro-2,3-propene oxide had little effect on or enhanced metabolite formation from DMBA in vitro.