Modulation of Repair of DNA Damages Induced by Nitrosamines

The persistence of various DMA alkylation products (7-methyl-guanine, 3-methyladenine and 06-mcthylguanine) was examined in the liver of rats following chronic administration of low doses of dinethylnitrosamine. The treatment resulted in an increased removal of 0 6-methylguanine due to an inducible DNA repair process. These observations in rat liver arc discussed with reference to a similar inducible repair process observed in E. coli exposed to low doses of the alkylating agent, N-methyl-N’-nitro-N-nitrosoguanidine.