Nitrosamine Studies: Induction of Lung Adenomas by Concurrent Administration of Sodium Nitrite and Secondary Amines in Swiss Mice<xref ref-type="fn" rid="FN2">2</xref>

Abstract

Piperazine (6.25 g/kg of food), morpholine (6.33 g/kg of food), and N-methylaniline (1.95 g/kg of food) given together with sodium nitrite (1.0 g/liter of drinking water) to Swiss mice resulted in a highly significant increase in lung adenoma incidence. This increase was more pronounced in males than in females. Dimethylamine hydrochloride (5.9 g/kg of food) was ineffective when given with nitrite, probably because of the strong basicity of the amine. Dinitrosopiperazine given as a 40 mg/liter solution in the drinking water, nitrosomorpholine (80 mg/liter), dimethylnitrosamine (10 mg/liter), and N-nitroso-N-methylaniline (70 mg/liter) increased the number of lung adenomas per mouse tenfold to thirtyfold over control untreated mice. Treatment with sodium nitrite alone or with the secondary amines alone produced no effect. The data strongly suggest that the induction of lung adenomas in animals treated with these secondary amines and nitrite is due to in vivo nitrosation (presumably in the stomach) with the formation of carcinogenic nitrosamines.