Involvement of vasoactive intestinal peptide (VIP) on ovarian physiology

In addition to the central nervous system, vasoactive intestinal peptide (VIP) containing nerves have been described throughout the female genital tract. VIP is reported to be produced by nerves fibers innervating follicles at all stages of development in rodents. There is growing evidence that VIP and their receptors play important roles in the local regulation of ovarian physiology mostly through cAMP pathway. It has been reported that VIP regulates the ovarian follicle survival and growth, oocyte maturation, ovulation and steroidogenesis. Studies also demonstrated that VIP inhibits apoptosis of rat follicles and is an important factor for the gro wth of preantral follicles enclosed in caprine ovarian tissue. Even though the addition of VIP to the culture med iu m did not improve in vitro maturation and fert ilization of oocytes, it has been shown to stimu late ovulation in perfused rat ovaries. VIP is also involved in the regulation of steroidogenic activity. Therefore, this review aims to summarize current data on the importance of VIP on ovarian physiology.