[Stomach adenocarcinoma induction in rats by the combined administration of N-methyl-N-nitroso-N'-nitroguanidine precursors].

N-methyl-N'-nitroguanidine and sodium nitrite were administered as drinking water to non-inbred male rats at the level of Img/ml for over two years. Gastric adenocarcinomas were produced in 43.7% of rats surviving for 15.5 months when the first tumor was noticed. Gastric mucous membrane of other rats had morphological changes analogous to those induced by N-methyl-N-nitoroso-N'-nitroguanidine (MNNG). The results obtained indicate endogenous synthesis of MNNG from precursors in the stomach of rats.