Comparative Studies With Different Doses of N-Nitrosomorpholine, N-Nitrosopiperidine, N-Nitrosomethylurea, and Dimethylnitrosamine in Syrian Golden Hamsters
A total of 520 Syrian golden hamsters (Mesocricetus auratus) was treated subcutaneously with one-fifth, one-tenth, or one-twentieth LD50 N-nitrosomorpholine (NM), N-nitrosopiperidine (NP), N-nitrosomethylurea (NMU), or dimethylnitrosamine (DMN). The carcinogenicity of these compounds demonstrated selective organotropism. NM, as well as NP, resulted in 65–100% tracheal papillary tumors, dependent upon the applied dose level; however, NM induced a higher incidence of tumors in the nasal cavities than did NP. A slight effect was observed in the lungs after treatment with NM. NMU induced up to 65% sarcomas localized at the site of injection, and in 7% of the animals papillomas of the forestomach were seen. With DMN application, overlapping hepatotoxic and carcinogenic effects were observed. Lower doses increased the survival rate, but tumor incidence was reduced only with the cyclic compounds.