Patterns of synthesis and secretion of sulfated glycosaminoglycans in primary cortical and cerebellar astrocytes in vitro

We determined the amounts of [S-35]-glycosaminoglycans (GAGs) found on the intracellular, pericellular and extracellular compartments of primary cultu res of astrocytes derived from newborn rat cortex and cerebellum in vitro. Our results show that the greatest portion of newly synthesized GAGs were f ound in different cellular compartments depending on the source of the astr ocytes. In the cells derived from the cerebellum, the proportion of [S-35]- GAGs secreted to the culture medium preponderates over the amount found in the two other compartments, whereas cells derived from the cortex accumulat ed higher proportions of [S-35]-GAGs in the intracellular compartment than in the two other compartments. Cortical and cerebellar glial cells synthesi sed and secreted heparan sulfate (HS) and chondroitin 4-sulfate (C-4S). HS was predominantly accumulated on the pericellular surface, while C-4S was m ostly secreted to the culture medium. Beside the difference on the distribu tion of total [S-35]-GAGs among the three cellular compartments, no differe nce was observed on the relative proportions of HS and C-4S within each com partment. By defining the source of GAGs, the present study may help to com plement and extend information on biosynthesis of these compounds by mammal ian glial cells. (C) 2000 Editions scientifiques et medicales Elsevier SAS.