Natural and accelerated docosahexaenoic acid accumulation in the prenatal rat brain

The quantity and distribution of docosahexaenoic acid (DHA) in major brain phospholipids (PL) was examined in the fetal rat brain before birth, using thin-layer and capillary column gas chromatography. A rapid increment of DHA content of about 187 micrograms/g brain/day was observed between 17 to 20 days gestation, as opposed to 39.3 +/- 2.9 micrograms/g brain/day prior to that. Single intraamniotic injections of 5 microL ethyl-docosahexaenoate (Et-DHA) (12 microM, 4.25 mg) administered to 17-day-old fetuses were used to examine the uptake of DHA into brain PL. Three days following injection, the amount of n-3 polyunsaturated fatty acids increased by 28% compared to ethyl-oleate (Et-Ole) injected fetuses. Compared to the n-6 fatty acid family, the relative amount of DHA increased in the phosphatidylserine (PS), phosphatidylethanolamine and phosphatidylcholine (PC) lipids by 15 (P = 0.02), 13 and 14%, respectively. A major increase in the pool size of phosphatidylinositol and PS (110 and 50.3%, respectively), and a decrease in PC (8.2%) were observed 3 d after Et-DHA as compared to Et-Ole administration. The data suggest that a single intraamniotic administration of Et-DHA can modulate membrane PL content and alter PUFA composition.