The induction of sister-chromatid exchanges in Chinese hamster ovary cells by some epoxides and phenolic derivatives of benzo[a]pyrene.

The induction of sister-chromatid exchanges in Chinese hamster ovary cells by in vivo treatment with a number of epoxy and phenolic derivatives of the carcinogenic polycyclic hydrocarbon, benzo[a]pyrene, has been investigated. Of the 3 vicinal diol-epoxides tested the anti-isomer of the bay-region 7,8-dihydrodiol-9,10-epoxide was the most active since, when tested at a 10-fold lower concentration, it induced the same number of sister-chromatid exchanges as the corresponding syn-isomer. The anti-isomer of the non-bay-region 9,10-dihydrodiol-7,8-epoxide was much less active than either of the bay-region diolepoxides and its activity was comparable with those of the 2 simple oxides tested, the K-region 4,5- and the non-K-region 7,8-oxides, of benzo[a]pyrene. The 2 phenols tested, 3- and 4-hydroxybenzo[a]pyrene, were only slightly active in inducing sister-chromatid exchanges.