IGFBP-3
Insulin growth factor binding protein - 3 binds insulin like growth factor I and II and controls IGF access to receptors, modulating IGF's action. Serum IGFBP-3 levels are low at birth, rise rapidly during the first weeks of life, reach a peak at the time of puberty and fall during adult life. Measurement of IGFBP-3 levels is proposed to be the last indicator of GH deficiency.