A comparison of the distribution, metabolism and excretion of ethylenethiourea in the pregnant mouse and rat

Abstract

Pregnant mice and rats were treated by stomach intubation on day 15 of gestation with 240 mg/kg of ethylenethiourea (ETU) made up in part with radiolabeled ETU. Animals were sacrificed at specific times post‐treatment, and maternal tissues, fetus, urine and feces were collected for determination of radioactivity. Maternal and fetal tissue levels of ETU were similar at three hours post treatment; thereafter, the mouse (maternal and fetus) showed much less ETU than the rat. The t½ of ETU elimination from the maternal blood was 9.4 and 5.5 hours for the rat and mouse, respectively. Analysis of urine by thinlayer chromatography and radiochromatography revealed that the mouse and rat metabolized ETU by different pathways. Furthermore, the mouse is able to metabolize ETU to a greater extent than the rat.