Some Unusual Findings on the Carcinogenic Action of Urethane in Mice

Abstract

THE induction of pulmonary tumours in mice following ethyl carbamate (urethane) treatment was originally described by Nettleship, Henshaw and Meyer¹ and has been confirmed by numerous workers. Similar effects of urethane in the rat have been noted by Jaffe². The lung tumours described have been adenomata, usually multiple, appearing by three months after oral or injected, single or multiple doses of urethane (solutions of 5 or 10 per cent). In histological appearance the tumours are the same as spontaneous lung tumours arising in strain A mice and are of relatively low-grade malignancy. Successful transplantation has not been reported. The findings reported below were obtained on Rockland ‘Swiss' albino mice in experiments investigating the carcinogenic action of urethane. The preliminary results obtained are so unusual that they are presented in a very incomplete form, so that the effects may be looked for by other investigators and the apparent action considered by those using urethane for clinical therapy. More detailed results will be presented shortly from a repetition of these and other experiments now in progress.