[Somatomedins/insulin-like growth factors (IGFs): chemical and functional characteristics].

The insulin-like growth factors constitute a family of peptides which have structural homology with proinsulin, and which possess broad anabolic and mitogenic action in wide variety of tissues. The two main forms of IGFs in serum of adults are insulin-like growth factor I (IGFI) and insulin-like growth factor II (IGFII). IGFI appears to be the major growth factor involved in postnatal growth and is believed to mediate most (if not all) of the growth promoting effects of growth hormone (GH). IGFII may be involved in embryonic and fetal growth. It is the aim of this article to present an account of recent advances in the understanding of the origins, functions, and clinical significance of these peptides. Particularly the role of IGFs in fetal growth during normal and diabetic pregnancies.