The effects of cytokines on the growth and differentiation of glial cells in culture were evaluated to confirm that cytokines could modify the number and function of glial cells. Proliferation of glial cells was determined by the 3H-thymidine uptake and the double immunostain with anti-cell specific marker and anti-bromodeoxyuridine(BrdU) antibody. To check the effect on the differentiation of glial cells, the amount of glial fibrillar acidic protein(GFAP) and the activity of glutamine synthetase(GS) were measured in astrocytes. And also the amounts of myelin basic protein(MBP) and the activity of 2 ,3 -cyclic nucleotide phosphohydrolase(CNPase) were measured in oligodendrocytes. Among the cytokines used, only interleukin-1β(IL-1β) stimulated the growth of type 1 and type 2 astrocyte as well as 0-2A precursor cell. When the functional changes in these glial cells by cytokines were tested, IL-1β did not increase GFAP content in type 1 and type 2 astrocyte, but IL-1β increased GS activity in type 1 astrocyte, and slightly decreased this enzyme activity in type 2 astrocyte. Also interleukin-2(IL-2) and interferon-γ (IFN-γ) inhibited the activity of GS in type 1 and type 2 astrocyte. On the other hand, all cytokines used did not modify the growth and differentiation in oligodendrocytes. From these results we could suggest that IL-1β increases the growth of type 1 and type 2 astrocyte and also promotes the development for 0-2A precursor cell to type 2 astrocyte.
