THE ACCUMULATION OF ARACHIDONATE AND DOCOSAHEXAENOATE IN THE DEVELOPING RAT BRAIN

Abstract—Fatty acids typical of grey matter lipids (C20:4 and C22:6) and of myelin lipids (C20:1 and C24:1) were estimated in developing rat brains. The polyenoic fatty acids (C20:4 and C22:6) are synthesized from the essential fatty acids (C18:2 and C18:3). The results showed that more than 50 per cent of the adult content of the brain polyenoic acids were laid down by day 15. In contrast, the fatty acids characteristic of myelin lipids did not appear in significant quantities until after this time. These findings distinguish biochemically the different periods of brain development associated firstly with cell division (formation of neurons and glial cells) and secondly with myelination. It is of special interest that the period of cell proliferation is accompanied by the appearance in brain lipids of long‐chain polyenoic acids derived from the essential fatty acids.