OVGP1 and osteoporosis: OGP (10–14) (G36G), the C-terminal pentapeptide cleaved from OGP (H-Tyr-Gly-Phe-Gly-Gly-OH), is the bioactive form of OGP that directly regulates the differentiation of progenitor rat bone marrow mesenchymal stem cells (BMSCs) into osteoblasts and adipocytes, thus playing a role in the treatment of osteoporosis [9].