title: Use of Aroclor 1254-induced rat liver homogenate in the assaying of promutagens in Chinese hamster ovary cells.
abstract: Seven promutagens belonging to two chemical classes--polycyclic aromatic hydrocarbons (PAHs) (benzo[a]pyrene, dimethyl benz[a]anthracene, 3-methylcholanthrene, fluoranthene) and alkyl nitrosamines (dimethyl, diethyl, and dibutyl nitrosamine)--were studied in Chinese hamster ovary (CHO) cells. Findings of practical importance in the use of Aroclor 1254-induced rat liver homogenate (S9) in the CHO/hypoxanthine-guanine phosphoribosyl transferase (HGPRT) mutation assay were made. Our novel findings are (1) the inclusion of CaCl2 in the S9 cofactor mixture dramatically decreased the cytotoxicity of S9, and (2) different S9 optimum concentrations were observed for structurally similar promutagens. The inclusion of CaCl2 in the S9 cofactor mixture and the testing of each chemical of unknown S9 requirement at several S9 concentrations are therefore recommended for assaying promutagens in the CHO/HGPRT mutation assay.
mesh_terms: D000818:Animals; D001140:Aroclors / Q000494:pharmacology*; D002122:Calcium Chloride / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D020111:Chlorodiphenyl (54% Chlorine); D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D009152:Mutagenicity Tests; D009153:Mutagens / Q000633:toxicity*; D009154:Mutation; D010053:Ovary; D011078:Polychlorinated Biphenyls / Q000494:pharmacology*; D051381:Rats
chemical_list: D001140:Aroclors; D009153:Mutagens; D020111:Chlorodiphenyl (54% Chlorine); D011078:Polychlorinated Biphenyls; D007041:Hypoxanthine Phosphoribosyltransferase; D002122:Calcium Chloride