Fatty acids of cerebrosides in different regions of the developing foetal brain.

The fatty acid composition of cerebrosides of developing foetal human brain and regional variations, if any, during intrauterine life were studied. While palmitic and stearic acids were the predominant normal fatty acids throughout intrauterine life, long chain fatty acids, like lignoceric and nervonic acids, which were low at early gestational ages, rapidly accumulated at term. Regional differences were observed in the concentrations of long chain normal fatty acids especially at term. Medulla oblongata showed a greater accumulation of long chain fatty acids as compared to the cerebellum and cerebrum. The distribution of 2-hydroxy fatty acids in different regions showed a pattern predominantly that of long chain carbon units, even at 34 wk of foetal life. A higher ratio of lignoeric to stearic acid in the case of normal fatty acids, probably indicative of chain elongation, was also evident in the case of medulla oblongata and cerebellum as compared to the cerebrum. The significance of these qualitative alterations in relation to rapid growth of brain prior to term and the process of myelination has been discussed.