Clinical Information

Insulin-like growth factors 1 and 2 (IGF-1, IGF-2) are small polypeptides involved in the regulation of cell growth. IGF-1 and IGF-2 are bound to insulin-like growth factor binding proteins, six of which have been described. IGFBP-3 is the predominant of these, binding ~95% of circulating IGF-1 and IGF-2. 

IGF-1 serves as the major mediator of the anabolic and growth-promoting effects of growth hormone. Secretion patterns of IGF-1 and IGFBP-3 mirror each other, and are primarily growth hormone dependent. In contrast to growth hormone production, which is pulsatile and demonstrates significant diurnal variation, IGF-1 and IGFBP-3 levels exhibit only minor fluctuations. Given that, serum measurements of IGF-1 and IGFBP-3 represent a more stable assessment of growth hormone production, and aid in the evaluation of growth disorders and growth hormone deficiency.