LECITHIN SYNTHESIS IN FETAL PRIMATE TISSUES AS MEASURED in vivo.

The choline incorporation pathway (I) accounts for >95% of de novo lecithin synthesis in fetal monkey lung slices. This in vivo study examined the incorporation of 3H-choline and 14C-ethanolamine into lecithin. Isotopes were injected into 140-148 day fetal Rhesus monkeys via an interplacental venous catheter maintaining the integrity of the amniotic cavity and the circulation. After 2 hrs, 3H/14C labeling in TLC-isolated lecithin was measured in various organs. Results (% transported precursor incorporated into lecithin) from 4 fetuses