Unique bioactivities of bone morphogenetic proteins in regulation of reproductive endocrine functions

Remarkable progress has been made in understanding the mechanism by which growth factors and oocytes can regulate the development and function of granulosa cells. Insufficiency of two oocyte-specific growth factors, growth differentiation factor-9 and bone morphogenetic protein (BMP)-15, cause female infertility. Expression of mRNA and/or protein for the BMP system components, including ligands, receptors and intracellular signal transduction factors, was demonstrated in cell components of growing preantral follicles, and biofunctional experiments have further revealed many important roles of the BMP system in regulation of reproductive function. In this review, recent advances in studies on biological actions of BMPs in ovarian folliculogenesis and in related endocrine tissues are discussed.