INSL3 Plays a Role in the Balance between Bone Formation and Resorption

We have recently demonstrated that the disruption of the INSL3 hormonal system, as observed in humans with mutations in the RXFP2 gene and in Rxfp2-deficient mice, might affect the equilibrium of the osteoblast-osteoclast system, resulting in an imbalance between bone formation and bone resorption that may result in reduced bone mass. In the present study we have better characterized the in vitro effects of INSL3 on human osteoblasts. Stimulation of human primary osteoblasts with INSL3 at serial concentrations (1 pM, 1 nM, and 1 mu M) induced a dose-dependent increase in osteoblast proliferation and expression of specific ostcoblast genes.