Carcinogenic Potency of N‐Nitrosomethyl(2‐hydroxypropyl)amine and Other Metabolic Relatives of N‐Nitrosobis(2‐hydroxypropyl)amine by Single Intraperitoneal Injection on the Lung of Rats

The carcinogenic effects of a single intraperitoneal injection of N‐nitrosobis(2‐hydroxypropyl)‐amine (BHP) or its metabolic relatives, N‐nitrosomethyl(2‐hydroxypropyl)amine (MHP), N‐nitrosobis(2‐oxopropyl)amine (BOP), N‐nitroso(2‐hydroxypropyl)(2‐oxopropyl)amine (HPOP) and N‐nitroso‐2,6‐dimethylmorpholine (NDMM), were studied in male Wistar rats. The main target organ of these nitrosamines proved to be the lung, followed by the thyroid. Lung lesions were induced in a dose‐dependent manner with total lung tumor incidences reaching 55% to 100%. BHP, MHP, HPOP and NDMM all caused lung carcinomas to develop (22% to 44% incidence), whereas BOP was only associated with adenomas. On the basis of dose administered and incidence of carcinomas, MHP appeared to be the most potent lung carcinogen of the five nitrosamines investigated. Smaller numbers of neoplasms were also induced in the kidney, urinary bladder, esophagus and intestine at differing rates by these nitrosamines.