Ontogeny of the hypothalamic-pituitary (growth hormone)-insulin-like growth factor-I axis in birds

Abstract

SYNOPSIS. The ontogeny of the hypothalamic-pituitary growth hormone (GH)-insulin-like growth factor- (IGF-) I axis particularly in birds is considered. Moreover, the ontogeny of IGF-II and IGF-binding proteins (IGF-BPs) are also discussed. Models for the axis in fetal and postnatal mammals, embryonic and posthatching birds, together with nutritionally-deprived mammals and birds are suggested as are the evolutionary changes in the axis.