Abstract
Insulin like growth factor-1 (IGF-1) is a potent stimulator of bone formation, and stimulates matrix formation and cell proliferation of osteoblastic cells. The effects of IFG-1 on bone are determined not only by its concentration but also by the concentrations of its specific binding proteins (IGFBPs). Among these IGFBPs, IGFBP-3 is the major binding protein in the circulation. IGFBP-3 has been shown to potentiate or inhibit the action of IGF-1 on bone depending on the experimental conditions. In vitro experiment demonstrated that IGFBP-3 potentiates the action of IGF-1 by increasing the stability of IGF-1 and by increasing cellular association o IGF-1. In vivo study analyzing the effect of the intermittent administration (once a week and three times a week) on bone in rats' hind leg immobilized by sciatic neurectomy combined with ovariectomy (OVX-NX) demonstrated an increase in the bone mass and bone formation rate. These results suggest that the IGF-1/IGFBP-3 complex may play an important role in the maintenance of bone turnover and may serve as a potent medical tool for the treatment of bone loss.
