Mutagenicity of ethyl carbamate to lacZ- transgenic mice.

The mutagenicity of the rodent carcinogen ethyl carbamate (EC, urethane) has been assessed using the lacZ- transgenic mouse mutation assay (Muta Mouse). In two separate experiments a single i.p. dose of 900 mg/kg urethane followed by a 14-16 day expression period yielded statistically significant (approximately 2-fold) increases in mutation frequency (MF) in the lung and liver of the mice. In the second experiment MF in the spleen and bone marrow was also assessed and statistically significant increases in MF were observed in each case. Concomitantly conducted bone marrow micronucleus assays gave 15.8- and 8-fold increases respectively in the incidence of micronucleated polychromatic erythrocytes in the two studies.