Abstract
Female ACI and Donryu rats were given 40, 20 or 10ppm solutions of N-methyl-N-nitrosourethane (MNUR) continuously in the drinking water. The resulting incidences of tumors were nearly 100% in all groups, animals of both strains showing dose-dependent mean survival times. In both strains of rats, the main target organs were restricted to the upper digestive tract and no strain differences between ACI and Donryu rats were found. Upper digestive tract tumors were found most frequently in the forestomach, followed by the esophagus and oral cavity and/or pharynx. Histologically, they were all squamous cell papillomas or carcinomas.
The organotropism of MNUR is compared with those of other N-alkyl-N-nitrosourethanes and also N-alkyl-N-nitrosoureas which have chemical structures analogous to N-alkyl-N-nitrosourethanes.
