Developmental change in the amount of polysialosyl glycopeptides isolated from the rat brain

Polysialosyl glycopeptides were coisolated with glycosaminoglycans by Pronase digestion of the whole brains of perinatal rats and could be separated from known glycosaminoglycans by two-dimensional electrophoresis on cellulose acetate film. The polysialosyl glycopeptides could not be obtained from fetal rat brain on day 13 of gestation, but began to be detected on day 14. The amount of polysialosyl glycopeptides was estimated from the dye concentration of the Alcian blue-stained spot in the electrophoretogram. The glycopeptide content increased almost linearly, on the basis of brain DNA, up to 10 days after birth. Thereafter, the content decreased rapidly, and hardly any polysialosyl glycopeptides could be isolated from the brain at approximately 30 days. This developmental change may be involved in morphogenesis and maturation of the brain. The polysialosyl glycopeptides could be isolated from the cerebellum, from the cerebrum, or from the brainstem of the neonatal rat. However, each region of the brain had a postnatal developmental change in glycopeptide content different from those of the other regions.