Assay of the mutagenicity of the carcinogens dimethylnitrosamine [DMN] and diethylnitrosamine [DEN] in salmonella typhimurium

ABSTRACT

The mutagenicity of DMN and DEN was assayed using Salmonella typhimurium TA 100. The mutagenic activation was detected by the pre-incubation of bacteria and nit-rosamine with liver S-9 fraction from rats pretreated with Aroclor 1254. A dose-response was seen both with increased amounts of nitrosamines and protein. The mutagenicity of DMN and DEN was significantly higher after pre-incubation at pH 6.0 compared with the pre-incubation at pH 7.2. However, the DMN demethylase activity decreased as the pH was lowered. Therefore, the demethylase activity is inversely correlated with the mutagenic response