THE INSULIN-LIKE GROWTH FACTOR-I BINDING-PROTEIN AXIS - PHYSIOLOGY, PATHOPHYSIOLOGY AND THERAPEUTIC MANIPULATION

Insulin-like growth factor-I (IGF-I) is a single-chain polypeptide whi ch has multiple metabolic actions and effects on the differentiation a nd proliferation of a wide variety of cell types. IGF-I has endocrine, paracrine and autocrine actions and is bound in the circulation to a complex system of binding proteins which alter its bioavailability and activity. Thus its physiology is complex and is altered in a number o f pathological states. This review will discuss these states and the a ctual and proposed therapeutic applications of recombinant human IGF-I (rhIGF-I).