Glia maturation factor beta regulates the growth of N18 neuroblastoma cells.

Glia maturation factor beta (GMF-beta) is a 17-kDa growth regulating protein isolated from the brain. The effect of bovine GMF-beta on neurons was tested on the neuroblastoma line N18 and the pheochromocytoma line PC12. GMF-beta inhibited the proliferation of N18 cells and promoted their neurite outgrowth, with an increase in neurofilament protein, but had no effect on PC12 cells. This was in contrast to nerve growth factor (NGF) which regulated PC12 but not N18. Acidic fibroblast growth factor (FGF), on the other hand, had a weak effect on PC12 but none on N18. Antisera against GMF-beta and NGF neutralized the biological activity of the corresponding growth factors but showed no cross-neutralization. Fluorescence visualization revealed the binding of GMF-beta to N18 cells but not to PC12 cells; the opposite was true with NGF.