Mutagenic activity of heterocyclic amines in Chinese hamster lung cells with diphtheria toxin resistance as a marker.

The mutagenicities of 8 heterocyclic amines, which had been purified from pyrolysates of amino acids and proteins, broiled fish and fried beef, were assayed in Chinese hamster lung cells (CHL cells) in culture in the presence and absence of a metabolic activation system, with diphtheria toxin resistance as a selective marker. 3-Amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) was the most mutagenic of the heterocyclic amines tested. 3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-9H-pyrido[2,3-b]indole (A alpha C), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1) and 2-aminodipyrido[1,2-a:3',2'-d]imidazole (Glu-P-2) showed mutagenic activity on CHL cells, their specific activities being in the order shown above. All the compounds except Trp-P-1 required the presence of a metabolic activation system for mutagenicity on CHL cells.