Differences between products of binding of 7,12-dimethylbenz[a]anthracene to DNA in mouse skin and in a rat liver microsomal system

Hydrocarbon-deoxyribonucleoside products from the DNA of mouse skin exposed in vivo to 7,12-dimethylbenz[a]anthracene are chromatographically the same as the products formed in mouse embryo cell cultures. These products, which are known to arise through the generation of a diol-epoxide in the 1,2,3,4-ring of the hydrocarbon, are chromatographically separable from products that result from reaction of the K-region oxide of this hydrocarbon with DNA. However, when 7,12-dimethylbenz[a]anthracene is bound to DNA in the presence of a microsomal system analogous to those used in various carcinogen detection systems, the hydrocarbon-deoxyribonucleoside products co-chromatograph with the K-region oxide products. Differences in the profiles of metabolites formed in mouse embryo cell cultures and rat liver microsomal systems are consistent with the differences between the DNA-bound products in these two systems.