Lung carcinomas induced by oral administration of N-bis(2-hydroxypropyl)nitrosamine in rats.

The oral administration of N-bis(2-hydroxypropyl)nitrosamine (DHPN) in drinking water induced lung tumors in high incidence in rats at 25 weeks. Histologically, they were adenoma, adenocarcinoma, squamous cell carcinoma, and combined squamous cell and adenocarcinoma. Metastases of adenocarcinoma were observed in regional lymph nodes. The development of tumors in other sites was seen in the liver, thyroid, kidney, ureter, urinary bladder, and pancreas. The incidence of lung tumor was distinctly higher than that of other sites. These results indicate that the target organ of DHPN was the lung and that oral administration of this chemical carcinogen was responsible for the development of lung carcinomas in rats.