Mutagenicity of urine and faeces after treatment of rats with known genotoxins.

In the present study the feasibility of using mutagenic activity in faeces and urine as indicator for exposure to mutagens and carcinogens was investigated. For this purpose faeces and urine of rats treated with known genotoxins were compared for mutagenicity in the Ames test and for induction of sister chromatid exchanges (SCE test) in Chinese hamster ovary cells. Faeces and urine of animals treated with 2-acetylaminofluorene, benzidine, furazolidone, benzo[a]pyrene or cyclophosphamide were positive both in the Ames test and in the SCE test, although the effects in the latter test were less clear than in the former. Treatment with the bladder carcinogen N-nitrosodibutylamine resulted in urine that was clearly positive in the Ames test and slightly positive in the SCE test. Faeces and urine of rats were positive in the SCE and negative in the Ames test after treatment with the liver carcinogen N-nitrosodiethanolamine, and negative in the Ames test after treatment with the liver carcinogen N-nitrosodimethylamine. Urine of rats treated with N-nitrosodimethylamine was also negative in the SCE test, faeces were not tested for SCE induction. The results show that glucuronidated and non-glucuronidated mutagens can be demonstrated in faeces and urine up to several days after treatment of rats with genotoxic agents and it is concluded that examination of faeces and urine side by side enlarges the possibility of detecting exposure of the body to mutagens.