Induction of digestive tract tumors and leukemias in Donryu rats by administration of 1-amyl-1-nitrosourea in drinking water.

The effects of administration of 1-amyl-1-nitrosourea (ANU) at doses of 400, 200, 100 and 0 ppm in the drinking water to Donryu rats of both sexes were studied. Tumors developed in 166/205 (81%) rats that received ANU, as compared with 9/34 (27%) control rats. The incidence of digestive tract tumors was highest (76%), followed by hematopoietic tissue (11%) and liver (9%) tumors. In females, mammary tumors were also found. There appeared to be a dose-response relationship among the 3 treated groups as regards the incidence of tumors of the hematopoietic tissues and the average survival time.