THE DEVELOPING CNS - A SCENARIO FOR THE ACTION OF PROINSULIN, INSULINAND INSULIN-LIKE GROWTH-FACTORS

The multifunctional cytokines of the family of insulin and insulin-lik e growth factors (IGFs) have not yet gained general recognition as ess ential cell signals for the development of the vertebrate nervous syst em, This is, in part, a consequence of previous constraints in our thi nking, focused for many years on the endocrine roles of these factors in late mammalian development and postnatal stages, The cellular distr ibution of the components of the insulin and IGFs signalling system in the developing mammalian and avian CNS is remarkably conserved. While receptors are widespread, the much less abundant factors and modulato ry proteins are highly regulated in time and space, Progression of neu ral development through the steps of cell proliferation, differentiati on, maturation and survival is stimulated, at least in culture, by pro insulin and insulin and the IGFs, Thus, these factors might be importa nt autocrine and paracrine signals during development of the CNS.