Biological effects of bovine glia maturation factor on glial cells in culture.

Optimal bioassay conditions for bovine glia maturation factor (GMF) were determined among glial cells from normal glioblasts to glioma cells. Rat glioblasts 4-8 days after subculture show the highest response t GMF with regard to morphological transformation and mitogenic activity. Bovine GMF enhances DNA synthesis of rat glioblasts at 12 h after stimulation; maximum incorporation of [methyl-3H]thymidine was detected at 18 h. GMF increases twofold the saturation density of rat glioblasts but does not alter that of C6 astrocytoma cells. The apparent inhibition of mitogenic activity of high doses of GMF is seen in both normal and malignant glial cells.