Abstract

The corpus luteum (CL) is a temporary endocrine structure in mammals, which is the site of intense capillary network (angiogenesis). The angiogenesis is a process of vascular growth that is mainly limited to the reproductive system in healthy adult animals, which enables the hormone-producing cells to obtain the oxygen, nutrients and also precursors necessary to synthesize and release different hormones essential for the maintenance of ovarian functions. Vascular endothelial growth factor (VEGF) is thought to play a paramount role in the regulation of normal and abnormal angiogenesis in the ovary, especially in the newly formed CL. Recent studies have also indicated that hypoxia is important for establishing the vascular system during the CL development, which induces hypoxia-inducible factor (HIF)-1a expression in luteal cells (LCs). Therefore, the molecular regulation of luteal VEGF expression during CL development becomes more important to be explored. Based on our recent research findings, the present review will clarify the role of HIF-1a signaling in VEGF-dependent angiogenesis during CL development. Investigations of the angiogenic mechanisms may lead to new strategies in treatment for fertility control and for some types of ovarian dysfunction, such as polycystic ovarian syndrome (PCOS), ovarian hyperstimulation syndrome (OHSS) and ovarian neoplasia.

Key words: Phosphatidylinositol 3-kinase (PI3K), mammalian target of rapamycin (mTOR), hypoxia-inducible factor (HIF)-1a, vascular endothelial growth factor (VEGF), prolyl-hydroxylase (PHD), corpus luteum.