On the nomenclature of the insulin-like growth factor binding proteins

Abstract

The insulin-like growth factors (IGF) I and II circulate in plasma complexed to carrier or binding proteins. Based on their chromatographically determined molecular size they have been designated 150–200 kDa and 30–40 kDa IGF binding proteins (BP). In recent years a growing number of proteins with IGF binding characteristics have been isolated from various body fluids, cell lines and in various species. Provisional terminology based on source, species or molecular size has become increasingly confusing. Thus far three distinct binding proteins have been fully characterized and their amino-acid sequence determined [1–9]. During a workshop on the IGF binding proteins held in Vancouver, June 17–19, 1989, a proposal was put forward to adopt the designation ‘IGFBP’, with the addition of an arabic numeral and letter prefix to indicate species specificity, as outlined in table 1. It should be stressed that until full amino-acid nucleotide or sequence data are available for any new IGF binding protein this designation should not be adopted, but rather an operative designation. It was the feeling of the participants of the meeting that the proposed terminology will allow for better communication both between scientists in the field and with other scientists.