Levels of sulfatide synthesis distinguish oligodendroglia in different stages of maturation.

In the central nervous system, oligodendroglia elaborate extensive quantities of membranes to form the multilamellar myelin sheath. Whether the production of extensive networks of processes by oligodendroglia in culture is a similar type of phenomenon as the formation of myelin is an unanswered question. Rat oligodendroglia, prepared by a modification of a differential shaking and plating method, elaborate extensive processes in culture. In contrast, bovine oligodendroglia, obtained by a bulk-isolation method, produce whorls of membrane lamellae, adjacent to the cell soma. The incorporation of various radiolabeled substrates into specific lipids was compared with the two cell types. It was found that rat oligodendroglia do produce myelin specific lipids, but at a lower level than bovine oligodendroglia which are actively synthesizing myelin lipids, especially cerebrosides, from a variety of substrates. Interestingly sulfatides are produced at a higher level in the cells not producing myelin, rat oligodendroglia. Other lipids that are associated with myelination (cerebrosides with alpha-hydroxy fatty acids and phosphatidylinositides) are produced at higher levels in bovine oligodendroglia. Thus it appears that the extension of processes by oligodendroglia in culture is a different phenomenon than the production of myelin membranes and requires lower levels of myelin lipids.