Nitric oxide signaling during meiotic cell cycle regulation in mammalian oocytes.

Nitric oxide (NO) acts as a major signal molecules and modulate physiology of mammalian oocytes. Ovarian follicles generate large amount of NO through nitric oxide synthase (NOS) pathway to maintain diplotene arrest in preovulatory oocytes. Removal of oocytes from follicular microenvironment or follicular rupture during ovulation disrupt the flow of NO from granulosa cells to the oocyte that results a transient decrease of oocyte cytoplasmic NO level.