FATTY-ACID COMPOSITION OF HUMAN BRAIN PHOSPHOLIPIDS DURING NORMAL DEVELOPMENT

The fatty acid composition of phosphatidylethanolamine (PE), ethanolam ine plasmalogens (EPs), phosphatidylserine (PS), phosphatidylcholine ( PC), and sphingomyelin was studied in 22 human forebrains, ranging in age from 26 prenatal weeks to 8 postnatal years. Phospholipids were se parated by two-dimensional TLC, and the fatty acid methyl esters studi ed by capillary column GLC, Docosahexaenoic acid (22:6n-3) increased w ith age in PE and PC, whereas arachidonic acid (20:4n-6) remained quit e constant. In EP, 22:6n-3 increased less markedly than 20:4n-6, adren ic (22:4n-6) and oleic (18:1n-9) acids being the predominant fatty aci ds during postnatal age. In PS, 18:1n-9 increased dramatically through out development, and 20:4n-6 and 22:4n-6 increased only until similar to 6 months of age. Although 22:6n-3 kept quite constant during develo pment in PS, its percentage decreased due to the accretion of other po lyunsaturated fatty acids (PUFAs), As a characteristic myelin lipid, s phingomyelin was mainly constituted by very long chain saturated and m onounsaturated fatty acids. Among them, nervonic acid (24:1n-9) was th e major very long chain fatty acid in Sp, followed by 24:0, 26:1n-9, a nd 26:0, and its accretion after birth was dramatic. As myelination ad vanced, 18:1n-9 increased markedly in all four glycerophospholipids, p redominating in EP, PS, and PC. In contrast, 22:6n-3 was the most impo rtant PUFA in PE in the mature forebrain.