Oxidative metabolites of the teratogen and transplacental carcinogen diethylstilbestrol in the fetal Syrian golden hamster.

14C-labelled diethylstilbestrol was administered orally, intraperitoneally, and intrafetally to 15-day pregnant hamsters and the radioactivity determined in the fetus, placenta, and maternal liver after six hours. Significant amounts of radioactivity were found in these tissues in every case, indicating maternal-fetal and fetal-maternal transfer of diethylstilbestrol. Part of the radioactivity found in the tissues could not be extracted even after excessive washing. This implied the presence of reactive metabolites. In the fetal and placental extracts, eight oxidative metabolites of diethylstilbestrol were identified by mass fragmentography as hydroxy- and methoxy-derivatives of diethylstilbestrol pseudo diethylstilbestrol, and dienestrol. The presence of oxidative metabolites in the hamster fetus and the covalent binding to tissue macromolecules are possibly associated with the fetotoxic effect of diethylstilbestrol.