An investigation in vitro of the exocytosis of lysosomal enzymes from C6 glioma cells.

The rates of exocytosis on the lysosomal hydrolase n-acetyl-beta D-glucosaminidase and beta-glucuronidase were measured in monolayer cultures of the C-6 glioma cell line. A comparison of the kinetics of release of the enzymes and the effects of cytochalasin B suggest that either intralysosomal localisation or the mechanism of release may be different for each enzyme. Evidence was obtained that exocytosis is accompanied by receptor-mediated endocytosis of hydrolases and the importance of the microtubular system in the maintenance of the exocytosis equilibrium was indicated by the effect of colchicine on the rate of extracellular accumulation of the enzymes.