EFFECT OF ETHYLENE THIOUREA ON CULTURED RAT EMBRYOS IN THE PRESENCE OF HEPATIC-MICROSOMAL FRACTION

To investigate whether the teratogenicity of ethylene thiourea (ETU) i s due to ETU per se or to its metabolites, rat embryos cultured in vit ro were exposed to 10 and 30 mu g/ml of ETU in the presence or absence of rat liver microsomal fraction (S9mix). In the absence of S9mix, th e incidence of morphological abnormalities increased dose-dependently. In the presence of S9mix, abnormal morphogenesis was almost absent in all embryos. These findings Suggest that teratogenicity of ETU is due to ETU per se.