STIMULATION OF MYENTERIC PLEXUS NEURITE OUTGROWTH BY INSULIN AND INSULIN-LIKE GROWTH FACTOR-I AND FACTOR-II

A defined culture medium containing insulin, insulin-like growth factor I (IGF-I) or insulin-like growth factor II (IGF-11) supported morphological development of myenteric plexus neurons derived from neonatal guinea pigs. Insulin increased neurite outgrowth 3-fold at concentrations as low as 0.2 nM. Similar significant and dose-dependent increases in neurite outgrowth were noted with IGF-I and IGF-II. Stimulation of neurite outgrowth was abolished by exposure to cytosine arabinofuranoside, an agent toxic to non-neuronal cells, implying that trophic effects of insulin or insulin-like growth factors require the presence of non-neuronal elements in culture.