Abstract
Urethan was administered to suckling rats in order to disclose its neoplastic potentialities in their various tissues. Male and female rats of Buffalo and Long-Evans strains were given five weekly, subcutaneous injections of urethan in a dose of 1mg/g body weight, beginning at 7 days of age. Untreated rats of both strains served as controls.
Seventy to 100% of the treated rats of both strains had one or more primary tumors at the time of death. A large strain difference was observed in the susceptibility of various organs to urethan carcinogenesis between Buffalo and Long-Evans strains. In Buffalo strain, the lymphoreticular tissues, mammary glands, and liver were the target organs, while the kidneys were the most susceptible in Long-Evans strain. Three B-cell adenomas of the pancreatic islets were also found in the treated rats of both strains.
