13-cis retinoic acid and murine pulmonary adenomas: a preliminary report

The inhibitory effect of 13-cis-retinoic acid was tested in conjunction with ethyl carbamate (urethane) induced murine pulmonary adenomas. Continuous feeding of the retinoic acid for 20 weeks did not significantly reduce the number of surface adenomas. No physical evidence of toxicity due to the vitamin A analog was observed in any of the mice. All mice showed a steady weight gain during the 20-week period, and there was no evidence of eye lesions, hemorrhage, bone fractures, fur changes or lethargy.