Quantitative analysis of cytotoxicity and mutagenicity of benzo[a]pyrene in mammalian cells (CHO/HGPRT system).

Chinese hamster ovary (CHO) cells in cell culture were utilized to study the cytotoxic and mutagenic activity of benzo[a]pyrene (BP). A liver homogenate (S9) prepared from Arochlor 1254 induced male Sprague-Dawley rats was employed to mediate the biotransformation of the promutagen. The dependence of the induction of 6-thioguanine(TG)-resistant mutants on parameters such as BP concentration, amount of S9 protein, ionic composition of the S9 mix and treatment time was determined. Under optimal conditions with a 5-h treatment time, BP mutagenicity can be described as 185 mutants/10(6) cells per microM BP per mg/ml S9 protein.