Carcinogenesis by a single dose of N-methyl-N-formylhydrazine.

Single sc injections of N-methyl-N-formylhydrazine were given to randomly bred Swiss mice. The females received 180 micrograms per gram of body weight, while two groups of males were treated with either 120 or 100 micrograms per gram of body weight. The treatment resulted in induction of tumors of lungs with an incidence of 40% in the females. In males treated with the higher and lower doses, the incidences of preputial gland tumors were 12 and 12%, respectively. Histopathologically, the tumors were classified as adenomas and adenocarcinomas of lungs, squamous cell papillomas, and carcinomas of preputial glands. N-Methyl-N-formylhydrazine is a constituent of the edible wild false morel mushroom Gyromitra esculenta, to which the human population is exposed in measurable quantities, sometimes at a single meal.