Comparative carcinogenicity of N-butyl-N-(3-carboxypropyl)-nitrosamine and N-butyl-N-(4-hydroxybutyl)nitrosamine for the urinary bladder of (C57BL/6 X DBA/2)F1 mice.

The carcinogenicity of N-butyl-N-(3-carboxypropyl)-nitrosamine [CAS: 38252-74-3; 4-(N-butyl-N-nitrosamino)butyric acid] in male and female (C57BL/6 X DBA/2)F1 mice was determined. N-Butyl-N-(3-carboxypropyl)nitrosamine given in the drinking water at a concentration of 3 mM (0.056%) for 13 weeks induced only carcinoma of the urinary bladder in both sexes. At 22-28 weeks, the incidences of bladder cancer in the male and female mice were 100 and 88%, respectively. These bladder tumors were classified histologically according to the frequency (%) of tumor type: pure transitional cell carcinoma, 42%; mixed (transitional cell carcinoma with squamous or glandular differentiation, or both), 28%; squamous cell carcinoma, 27%; and carcinoma in situ, 3%. No significant sex differences were observed. In comparative studies, the incidence of bladder cancer was 100% for both sexes after administration of 3 mM (0.052%) N-butyl-N-(4-hydroxybutyl)nitrosamine [CAS: 3817-11-6; 4-(butylnitrosoamino)-1-butanol] in the drinking water. The frequency of pure transitional cell carcinoma was 47%, which was not significantly different from that observed for the carboxypropyl compound. The frequencies of other types of bladder carcinoma induced by N-butyl-N-(4-hydroxybutyl)nitrosamine were the following: mixed, 8%; squamous cell carcinoma, 42%; and carcinoma in situ, 3%.