Susceptibility to urethane carcinogenesis of transgenic mice carrying a human prototype c-Ha-ras gene (rasH2 mice) and its modification by butylhydroxytoluene.

The susceptibility of rasH2 mice to urethane lung carcinogenesis and the modifying effects of butylhydroxytoluene (BHT) on development of pulmonary lesions were examined. Single i.p. injections of urethane at 250 mg/kg in males or 500 mg/kg in females induced alveolar/bronchiolar adenomas within 6 weeks. At 4 weeks after the injection with a dose of 1000 mg/kg, adenomas occurred in both sexes. BHT administration increased the multiplicity of hyperplasias observed 3 weeks after the urethane injection and additionally caused adenomas which did not occur in the urethane alone-treated animals. The overall data suggest the possibility of rapid assays for lung carcinogens using rasH2 mice.