Transformation of BALB/c 3T3 cells in vitro by the fungicides captan, captafol and folpet.

Cytotoxic and cell-transforming activities of the three fungicides, captan, captafol and folpet, have been studied in an experimental in vitro model by exposing BALB/c 3T3 cells to the chemicals with or without S-9 mix-induced bioactivation. Cytotoxicity of the three compounds was reduced in the presence of the metabolizing system. Each assayed pesticide displayed cell-transforming ability in the presence of the metabolizing system. The relative efficiency was: captafol > captan > folpet. Cell transformation was considered to be due to carcinogenesis-promoting activity. These data, obtained in a medium-term (6-8 weeks) experimental model, contribute to a better understanding of the action of the three pesticides in the multistep carcinogenesis process and provide more information concerning the oncogenic risk of these xenobiotic compounds for humans.