Co-mutagenic effects of 2-aminoanthracene and cigarette smoke condensate on smoker's urine in the Ames Salmonella assay system.

Cigarette smoke condensate (CSC) and cigarette smoker's urine (concentrated) (UC) were tested alone and in combination with direct and indirect mutagens for histidine reversion in the Ames Salmonella assay system. While both CSC and smoker's urine showed some mutagenic activity upon metabolic activation with S9-mix, each of them in combination with the aromatic amine 2-aminoanthracene (2AA) exhibited a synergistic effect on mutagenicity. Such a synergistic effect was not found when these agents were combined with the direct mutagens, ethylmethane sulfonate (EMS) and methylmethane sulfonate (MMS), or the indirect mutagens, benzo[a]pyrene (BP) and 9,10-dimethyl-1,2-benzanthracene (DMBA), tested in this study, nor was the synergistic effect observed when 2AA was tested with urine from a non-smoker. The results, thus, reflected a specificity of the co-mutagenic action of factor(s) in cigarette smoke or smoker's urine and 2AA. The significance of co-mutagens in carcinogenesis has been discussed and the importance of investigating co-mutagenesis particularly in the case of suspected human exposure to multiple environmental agents has been emphasized.