Induction of 6-thioguanine resistance, chromosome aberrations and SCE by dinitropyrenes in Chinese hamster ovary cells in vitro.

The ability of Chinese hamster ovary (CHO) cells to convert dinitropyrenes (DNPs) to mutagenic species has been investigated by examining the effects of 1,6-DNP and 1,8-DNP on three distinct end-points in this cell line. At concentrations ranging from 0.05 to 5 micrograms/ml both analogues induced increases in the frequency of 6-thioguanine-resistant mutants in CHO cells when exposure was limited to 3 h. This treatment time was also sufficient to permit the induction of sister-chromatid exchange and chromosome aberrations in CHO cells. The results obtained suggest that CHO cells, unlike mouse lymphoma L5178Y cells, possess an endogenous metabolic activity which is capable of bringing about the conversion of DNPs to their mutagenic form without a requirement for prolonged exposure periods and as such may be a more suitable cell line for the study of this class of compounds.