The metabolism of nerve terminal glycoproteins in the rat brain

The fate of [3H]fucose in subcellular fractions has been followed for a period of three weeks after intraventricular injection in the rat brain. Isolated synaptosomal membranes were examined by gel electrophoresis. Seven fucosyl glycoproteins with molecular weights ranging from 123,000 to 31,000 were detected by scintillation counting of transversely sliced gels and their specific activities determined. The half-lives of 6 of the membrane glycoproteins fell within the range 11-22 days. The smallest glycoprotein showed anomalous behaviour; its radioactivity did not fall significantly over the period of study. The results are discussed in relation to current concepts of fast axonal transport.