Changes in monogalactosyl diglyceride & other glyco & phospholipids in developing & aging chick cerebrum & cerebellum

Abstract

Changes in the concentrations of monogalactosyl diglyceride as well as other glycolipids, cholesterol and different species of phospholipids have been studied in cerebral and cerebellar regions of developing and aging chick brain. Very low levels of glycolipids are noticed in embryonic brain while nearly reaching adult levels by the 5th day after hatching, with only a slight increase occurring beyond this stage of life. The deposition of monogalactosyl diglyceride in cerebrum was found to be unique in that all the accretion of this liquid occurs between the 16th day of embryonic life and the 5th day after hatching: that is during a period characterised by a high rate of myelination. Beyond 5 days there was little increase in the concentration of this galactolipid. Significant amounts of both choline and ethanolamine phosphoglycerides are observed in the embryonic brain with a continued increase in the levels up to 120 days after hatching. Two-fold increases in the concentrations of sphingomyelin, phosphatidylserine and phosphatidylinositol are found between embryonic life and the 5th day post-hatching, with only a slight further enhancement of the levels throughout the rest of the life span studied. These results indicate that deposition of monogalactosyl diglyceride could be used as a sensitive and specific biochemical parameter to follow myelination.