Insulinlike growth factors (IGF-I and IGF-II), single-chain polypeptides structurally homologous to proinsulin, exert insulinlike metabolic effects and regulate the proliferation and differentiation of numerous cell types. IGFs are abundant in circulation and are produced under specific conditions by most tissues. The liver is the major source of circulating IGF-I, whereby growth hormone, in the presence of insulin, triggers IGF-I gene transcription. IGF-I acts in a paracrine manner in vivo to mediate many of the physiological activities of growth hormone. IGF-I action is modulated by six binding proteins (IGFBPs) that are degraded by specific IGFBP proteases.
ASJC Scopus subject areas
- Internal Medicine
- Endocrinology, Diabetes and Metabolism