The relationship between the levels of DNA-hydrocarbon adducts and the formation of sister-chromatid exchanges in Chinese hamster ovary cells treated with derivatives of polycyclic aromatic hydrocarbons.

The frequencies of the induction of sister-chromatid exchanges and the levels of deoxyribonucleoside-hydrocarbon adducts formed in Chinese hamster ovary cells that had been treated with either dihydrodiols or a diol-epoxide derived from polycyclic aromatic hydrocarbons were determined. Up to 6-fold increases in the incidence of these exchanges were observed when the cells were treated either with the dihydrodiols, trans-3,4-dihydro-3,4-dihydroxy-7-methylbenz[alpha]anthracene, trans-7,8-dihydro-7,8-dihydroxybenzo[alpha]pyrene or the diol-epoxide, (+/-)-r-7, t-8-dihydroxy-t-9,10-oxy-7,8,9,10-tetrahydrobenzo[alpha]pyrene but when the cells were transferred to media free of these compounds, there were rapid reductions in the frequency of these exchanges. When the exchanges were induced by the diol-epoxide, the decreases in frequency were paralleled by decreases in the levels of deoxyribonucleoside-diol-epoxide adducts that were present in hydrolysates of DNA isolated from the cells. There thus appears to be a close relationship between the frequency of sister-chromatid exchanges and the levels of deoxyribonucleoside-diol-epoxide adduct formation.