Lung Tumors in Rats Treated with N -Nitrosoheptamethyleneimine and N -Nitrosooctamethyleneimine ∗

Summary

Two new cyclic nitrosamines, nitrosoheptamethyleneimine and nitrosooctamethyleneimine, have been prepared and tested biologically by feeding to rats in drinking water, at two concentrations, 50 and 200 mg/liter. Both nitrosamines produced a high incidence of squamous carcinomas in the lung and of squamous tumors in the esophagus. The lower dose of the compounds did not seem less effective than the 200 mg/liter concentration. Nitrosooctamethyleneimine appeared to be a less potent tumorigen than nitrosoheptamethyleneimine, the latter giving rise to lung tumors after less than 16 weeks treatment, and to esophageal tumors after 7 weeks. Although large single doses of both nitrosamines caused rapid death of the animals with severe necrosis of the liver, there were no tumors or other lesions of the liver in animals treated chronically.