Incorporation of 14C-1-palmitate into rabbit fetal lipids in vivo

14C-1-palmitate was injected into rabbit fetuses in utero. Fetal liver, blood, carcass, and placenta collected after 15, 60, 180, and 360 minutes were analyzed for radioactivity in lipid classes. Incorporation differed with tissue and lipid. Highest total early specific activity was detected in plasma but later liver displayed the most extensive incorporation. Phospholipid incorporation was more rapid in all tissues than that of other glycerides. Plasma triglycerides did not display any radioactivity for 3 hours. Results point to multicentric origin of plasma lipids. Ready utilization of the palmitate indicates that maternal fatty acid transfer plays an important role in fetal lipid hemeostasis.