Insulin-like growth factor binding protein

The Insulin-like growth factor binding protein serves as a carrier protein for Insulin-like growth factor 1.

Approximately 98% of IGF-1 is always bound to one of 6 binding proteins (IGF-BP). IGFBP-3, the most abundant protein, accounts for 80% of all IGF binding. IGF-1 binds to IGFBP-3 in a 1:1 molar ratio.

IGF-BP also binds to IGF-1 inside the liver, allowing growth hormone to continuously act upon the liver to produce more IGF-1. This is important because proliferating IGF-1 + IGF-BP complex allow growth of the femur and the muscle.

There are seven genes:
 * IGFBP3
 * IGFBP3
 * IGFBP3