Inhibition of the localization of urethane in mouse tissues by ethanol

[ ethyl-1- 14C]Urethane in water or in 12% ethanol was administered orally to male A/JAX mice and 1 hr later the mice were frozen and processed for whole-body autoradiography to identify sites of localization of radioactivity. When the [ 14C]urethane was administered in water, radioactivity was localized in the liver and bile, the salivary, seromucous and Harderian glands, the bone marrow and pancreas and the stomach and intestinal epithelia. When the labelled urethane was administered in 12% ethanol, localization of radioactivity in each of these sites was almost completely inhibited; radioactivity was still seen within the lumen of the stomach and intestine. Using a defined chemical system, no transesterification was observed between urethane and 12% aqueous [ 2H 6]ethanol at pH 1.5 in 80 min. The inhibition of the localization of radioactivity in the tissues appears to be due most probably to blocking of the metabolism of urethane in tissues. This suggest that ethanol may inhibit the carcinogenicity of urethane in mice.