Glial cell growth-promoting factor in astrocytoma (C6) cell extracts.

The presence of glia maturation factor (GMF)-like activity was demonstrated in rat astrocytoma cells (C6 cells). The extracts of C6 cells enhanced the DNA synthesis of cultured glioblasts 3-fold at the maximum, inducing such morphological changes as extrusion of processes. C6 cells also showed a proliferative response to the extracts, though the responsiveness in terms of effective concentration of C6 extracts was about a half of the glioblast responsiveness. The extracts lowered growth rate of neuroblastoma cells and especially decreased their DNA synthesis without a morphological differentiation.