IGF-1 （Insulin-like growth factor-1） is a major hormonal mediator of statural growth. Under regular circumstances，GH （growth hormone） binds to its receptor in the liver，and other tissues，and stimulates the synthesis/secretion of IGF-1. In target tissues，the Type 1 IGF receptor，that is homologous to the insulin receptor，is activated by IGF-1，leading to intracellular signaling which stimulates multiple processes leading to statural growth. IGF-1 metabolic actions are partly directed at stimulating the uptake of glucose，fatty acids，and amino acids so that metabolism supports growing tissues.
