Functional dissociation of dual activities of glia maturation factor: inhibition of glial proliferation and preservation of differentiation by glial growth inhibitory factor.
Glial growth inhibitory factor (GGIF), derived from the culture medium of mouse neuroblastoma cell (NAs-1), lowered the DNA synthesis and cell multiplication of normal rat glioblasts induced by glia maturation factor (GMF). The inhibitory action of GGIF depended on the concentration of GMF in the culture medium, and was of an uncompetitive type on kinetic analysis. GGIF showed the inhibitory activity at a late stage of the G1 phase or early stage of the S phase. The factor, however, failed to inhibit the differentiation-promoting activity of GMF. The data strongly suggest that the dual activities of GMF, the promotion of glial proliferation and differentiation, may be elicited by mutually independent intracellular processes.
D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003470:Culture Media; D004247:DNA / Q000096:biosynthesis; D020904:Glia Maturation Factor; D006131:Growth Inhibitors / Q000494:pharmacology*; D008565:Membrane Proteins / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D009457:Neuroglia / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D013936:Thymidine
D003470:Culture Media; D020904:Glia Maturation Factor; D006131:Growth Inhibitors; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C031717:growth inhibitory proteins; D004247:DNA; D013936:Thymidine