Research on the Carcinogenic Activities of N-Nitrosopyrrolidine, N-Nitroso-2-pyrrolidone, and N-Nitroso-5-methyl-2-pyrrolidone

Abstract

N-Nitrosopyrrolidine (I), N-nitroso-2-pyrrolidone (II), and N-nitroso-5-methyl-2-pyrrolidone (III) were prepared, and fed in drinking water to male Sprague-Dawley rats for 365 days to compare the effects of their chemical consitution on the carcinogenicity of these compounds. In the animals surviving beyond 276 days, I induced hepatocellular carcinoma in 15 of 18 animals (83%), II induced colon carcinoma in 1 of 15 animals, and III did not induce carcinoma in any of 16 animals. Obviously I, II, and III have entirely different pattern of carcinogenicity. LD₅₀ (oral, measured by Litchfield-Wilcoxon method in male ddY mice) increased in the order of II, III, and I, and the mutagenic activity ("Rec-assay, " using B.subtilis mutant, H-17 and M-45) increased in the order of I, III, and II. These orders have little relation to their carcinogenicity.