Secreted peptides as regulators of neuron-glia and glia-glia interactions in the developing nervous system.

Secreted peptides of the nervous system help to regulate neuron-glia and glia-glia interactions during development. These regulatory factors, referred to as glia-promoting factors (GPFs), act on specific classes of glia and include oligodendroglia-stimulating peptides, interleukin-1 (IL-1), colony-stimulating factors (CSF), and fibroblast growth factor (FGF). The maturity of secretory and target cells determines, in part, the ability of a factor to influence glial proliferation, activation, or differentiation. During neural development, GPFs help to control such fundamentally important events as cell movement, neurite outgrowth, and myelination.