Description
Insulinlike growth factor I, also known as somatomedin C, is the dominant effector of growth hormone and is structurally homologous to proinsulin. Human IGFI is synthesized as two precursor isoforms with N and alternate Cterminal propeptides. IGFI induces the proliferation, migration, and differentiation of a wide variety of cell types during development and postnatally. IGFI regulates glucose and fatty acid metabolism, steroid hormone activity, and cartilage and bone metabolism. It plays an important role in muscle regeneration and tumor progression. IGF I binds IGFI R, IGFII R, and the insulin receptor, although its effects are mediated primarily by IGFI R. IGFI association with IGF binding proteins increases its plasma halflife and modulates its interactions with receptors