Genotoxicity of a variety of nitroarenes in DNA repair tests with human hepatocytes.

The genotoxicities of 8 nitroarenes, i.e., 1-nitropyrene, 1,3-dinitropyrene, 1,6-dinitropyrene, 1,8-dinitropyrene, 2,7-dinitrofluorene, 3-nitrofluoranthene, 1-nitro-3-hydroxypyrene and 1-nitro-3-acetoxypyrene, were examined in DNA repair tests using human isolated hepatocytes. Out of the tested nitroarenes, 5 compounds, i.e., 1-nitropyrene, 1,3-dinitropyrene, 1,6-dinitropyrene, 1,8-dinitropyrene and 1-nitro-3-acetoxypyrene, clearly elicited positive responses of DNA repair. Among the chemicals which elicited positive responses, the levels of unscheduled DNA synthesis induced by the three dinitropyrene isomers were much higher than those of the other nitroarenes. Three chemicals, i.e., 2,7-dinitrofluorene, 3-nitrofluoranthene and 1-nitro-3-hydroxypyrene, elicited negative responses. The negative responses of 2,7-dinitrofluorene and 3-nitrofluoranthene, which had been positive in DNA repair tests with rodent hepatocytes, suggest some species differences between humans and rats in the metabolic activity of hepatocytes toward these agents.