Synthesis of myelin glycosphingolipids by isolated oligodendrocytes in tissue culture.

Isolated lamb oligodendrocytes in tissue culture were tested for their ability to express differenciated functions related to the synthesis of myelin. Galactocerebrosides and sulfatides are highly enriched in myelin and are recognized as markers for myelination. Hence, we followed the synthesis of these glycosphingolipids. At selected times, monolayer cultures of cells were double labeled for 60-72 h with [3H]galactose and H2 35SO4. Glycosphingolipids were separated and identified by thin layer chromatography. During the first week in tissue culture, there was gradual decline in incorporation of both isotopes relative to the values, obtained for freshly isolated cells. However, by 3 weeks high levels of H2 35SO4 incorporation into sulfatide and [3H]galactose into cerebrosides were found. A complex pattern of incorporation ensued after this peak which varied for each particular glycosphingolipid. It is concluded that: (1) cultured oligodendrocytes retain the capacity to synthesize components of myelin; (2) since the isolated cells have already been involved in myelination, these cultures afford a unique model to study remyelination' amd (3) these cells provide a good system to study the properties of oligodendrocytes.