Comparison of mutagenicities of N-nitrosamines on Salmonella typhimurium TA100 and Escherichia coli WP2 uvrA/pKM101 using rat and hamster liver s9.

The mutagenicities of twelve N-nitrosamines were tested on Salmonella typhimurium TA100 and Escherichia coli WP2 uvrA/pKM101 in the presence of rat liver S9 or hamster liver S9 by "preincubation" and "pour-plate" assays. The following eleven N-nitrosamines were mutagenic: N-nitroso-N-dimethylamine; N-nitroso-N-diethylamine; N-nitroso-N-di-n-propylamine; N-nitroso-N-di-n-butylamine; N-nitroso-N-methyl-n- amylamine ; N-nitroso-piperidine; N-nitrosomorpholine; N-nitroso-N-methyl-piperazine; N-nitroso-N-methyl-benzylamine; N-nitroso-N-methyl- phenylamine and N-nitroso-N-phenyl-benzylamine. N-Nitroso-N-diphenylamine was not mutagenic. E. coli WP2 uvrA/pKM101 was more sensitive than S. typhimurium TA100 to the mutagenic actions of N-nitroso-dialkyl amines, N-nitroso- aklyl -aryl amines and N-nitroso- diaryl amines, but S. typhimurium TA100 was more sensitive to those of N-nitroso-cyclic amines. Hamster liver S9 was better than rat liver S9 for metabolic activation of N-nitrosamines, and the preincubation step enhanced the mutagenicities of N-nitrosamines.