Nitric Oxide and Ovarian Folliculogenesis

Ovarian follicles are the basic structural and functional unit of the mammalian ovary. Follicles contain an oocyte or female gamete, its surrounding granulosa cells, a basement membrane, and associated thecal cells. Development of the ovarian follicles from a small preantral follicle to the large pre-ovulatory follicle is key process in mammalian reproduction. From birth, ovary of the female contains a large number of immature, primordial/prenatral follicles. However, most of the follicles undergoes atresia and only few number of follicles reached to the ovulatory stage. The present knowledge of the exact mechanisms regulating in vivo folliculogenesis is limited. Knowledge of the processes that lead to the formation of mammalian oocytes, their arrangement in follicles, their growth and maturation, the relevant endocrine and locally produced factors that are involved in these processes, and the interactions between the oocyte and its surrounding nurturing cells is important to understand the aberrations in follicle development and to learn the physiological circumstances that are necessary for successful fertilization and implantation of embryo.