Effect of age and sex on lesions of the esophagus in Buffalo strain rats ingesting diethylnitrosamine.

Inbred Buffalo male and female rats, 4, 12, 24, and 52 weeks of age, ingested 0.0114% diethylnitrosamine in a semisynthetic diet. Both age and sex were important in the development of preneoplastic and neoplastic lesions of the esophagus. The 4-week-old male rats had notably more carcinomas of the esophagus than female rats of the same age; whereas, 12-week-old male rats had only slightly more carcinomas than the females. The incidence of esophageal lesions was about the same in 24-week-old males and females. Rats 52 weeks of age were not susceptible to esophageal carcinogenesis.