Josephy P D, Lord H L, Snieckus V A
Guelph-Waterloo Centre for Graduate Work in Chemistry, Department of Chemistry and Biochemistry, University of Guelph, Ontario, Canada.
Carcinogenesis. 1994 Mar;15(3):479-82. doi: 10.1093/carcin/15.3.479.
Dimethylnitrosamine (DMN) genotoxicity was evaluated in two test systems: induction of the umu operon (as measured by expression of a lacZ gene fusion) and mutagenicity (as measured by the Ames assay). Three Salmonella typhimurium strains were used; the strains differ in the level of expression of the enzyme acetyl CoA:arylamine N-acetyltransferase (NAT). We did not observe increased sensitivity in a strain with a plasmid-borne copy of the nat gene, and expressing very high levels of NAT activity. In contrast to a recent report, we conclude that NAT-dependent metabolic activation does not play a major role in the genotoxicity of this carcinogenic nitrosamine.
