The relationship between benzo(a)pyrene diol-epoxide-DNA adducts and mutagenicity in the CHO/HPGRT assay

We have studied the relationship between DNA adducts in Chinese hamster ovary (CHO) cells and mutagenicity as determined in the CHO/hypoxanthine-guanine phosphoribosyltransferase assay. The cells were treated with benzo(a)pyrene 7,8-diol (BP-diol) in the presence of a bioactivation system, S9 mix. DNA binding by bioactivation of BP-diol with S9 mix occurred with both stereoisomers of benzo(a)pyrene diol-epoxide (BPDE) in approximately equal amounts. The number of BPDE-DNA adducts (21-260 adducts/10(6) nucleotide base pairs) increased with increasing treatment concentrations of BP-diol (1.4-7.0 microM). A linear relationship was observed between the number of BPDE-DNA adducts and mutagenicity (89-605 mutants/10(6) cloneable cells) over the concentration range of BP-diol assayed.