DNA single-strand breaks by nitropyrenes and related compounds in Chinese hamster V79 cells.

The DNA single-strand breaks (SSB) induced by nitropyrenes and related compounds were studied in Chinese hamster V79 cells. 1-Nitropyrene (1-NP), 1,6-dinitropyrene (1,6-DNP), 1,8-dinitropyrene (1,8-DNP), 1-nitrosopyrene (1-NOP) and 1-aminopyrene (1-AP) caused DNA-SSB in the cells. 1-NP induced SSB most effectively among the compounds tested, though the mutagenic activity of 1-NP towards mammalian cells has been reported to be negative or marginal. 1-NOP induced SSB less effectively than 1-NP, though 1-NOP is assumed to be the intermediate to the ultimate metabolite. From in vitro experiments, this result could be explained, at least partly, by the detoxicating function of reduced glutathione (GSH) or other sulfhydryl materials.