Responses of the L5178Y mouse lymphoma cell forward mutation assay. V: 27 coded chemicals

Twenty‐seven chemicals were tested for their mutagenic potential in the L5178Y tk+/tk− mouse lymphoma cell forward mutation assay using procedures based upon those described by McGregor et al. (McGregor DB, Martin R, Cattanach P, Edwards I, McBride D, Caspary WJ (1987): Environ Mol Mutagen 9:143–160). Cultures were exposed to the chemicals for 4 hr, then cultured for 2 days before plating in soft agar with or without trifluorothymidine (TFT), 3 μg/ml. The chemicals were tested at least twice. Statistically significant responses were obtained with acid orange 10, aniline, benzaldehyde, o‐chloroaniline, chlorodibromomethane, cytembena, 1,2‐dibromo‐4‐(1,2‐dibromomethyl) cyclohexane, dieldrin, lithocholic acid, oxytetracycline, phenazopyridine HCl, 1‐phenyl‐3‐methyl‐5‐pyrazolone, sodium diethyldithiocarbamate, solvent yellow 14, tetraethylthiuram disulfide (disulfiram), 2,4‐toluene diisocyanate, and 2,6‐toluene diisocyanate. Apart from phenazopyridine HCl, acid orange 10, and solvent yellow 14, rat liver S9 mix was not a requirement for the mutagenic activity of these compounds. Chemicals not identified as mutagens were N‐4‐acetylaminofluorene, chlorpheniramine maleate, chlorpropamide, 1,4‐dioxane, endrin, ethylene glycol, iron dextran, methapyrilene, sodium(2‐ethylhexyl)alcohol sulfate, and 2,3,7,8‐tetra‐chlorodibenzo‐p‐dioxin.