Involvement of Bone Morphogenetic Proteins (BMPs) in Ovarian Function and Infertility

Advances in assisted reproduction techniques and the treatment of diseases known to be correlated with infertility such as polycystic ovary syndrome and premature ovarian failure require a better understanding of ovarian physiology. Despite the enormous quantity of information produced over the last two decades, the mechanisms controlling follicular development are not fully understood. Ovarian function is regulated by interactions between gonadotropins, follicle stimulating hormone, luteinizing hormone and local ovarian factors such as inhibins, activins, bone morphogenetic protein- 15 (BMP-15) and growth differentiation factor-9 (GDF-9), all members of the transformation and growth factor-β (TGF-β) superfamily. There is evidence of a functional ovarian BMP system with countless genes involved in normal follicular development and in fertility. The present review summarizes the ligands of the TGF-β superfamily, their receptors and signaling pathways and discusses the ovarian functions of the BMPs secreted by the oocytes as critical regulators of fertility.