Carcinogenic effects of different nitroso-compounds in Chinese hamsters. II. N-nitrosomorpholine and N-nitrosopiperidine.

A total of 320 Chinese hamsters (Cricetulus griseus) (CH) were subcutaneously (s.c.) treated with 1/5, 1/10, or 1/20 LD50 of N-nitrosomorpholine (NM) or N-nitrosopiperidine (NP). In the CH, NM and NP both produced up to a 100% rate of papillomas of the cheek pouch, tongue, pharynx, esophagus and forestomach. Occasionally squamous cell carcinomas also developed in these organs. A high rate of hepatomas was realized by NP.