IGFBP2 and osteoporosis: Another rat study also showed that a peptide containing the IGFBP2 receptor binding site enhanced bone mass in ovariectomized rats, leading the authors to conclude that IGFBP2 was necessary for maintaining bone mass in the absence of estrogen.[21] Furthermore, Zhou et al[22] discovered that IGF2BP-2 was a RNA-binding protein that stabilized the serum response factor mRNA to regulate cell proliferation and osteogenic differentiation, suggesting that IGF2BP-2 was a potential therapeutic target for treating osteoporosis.