Placental transfer of /sup 18/F in sheep

A surgical technique was employed on eight pregnant ewes wherein access is gained to the maternal and fetal circulations with the lamb in utero. Injections of F/sup 18/ were made into the animals in order to study various aspects of maternal-fetal fluorine metabolism. The data revealed that maternal plasma cleanance of F/sup 18/ is quite rapid and that fetal plasma levels are relatively low when compared to maternal levels. Uptake in fetal dental and skeletal tissues was shown. Injection of F/sup 18/ into the fetus revealed that transfer of fluorine from the fetus to the mother can occur.