Modulation of Female Reproductive Functions through Nerve Growth Factor: A Systematic Review

Nerve growth factor (NGF), which acts on receptors tropomyosin receptor kinase A and p75 neurotrophic receptor, is a member of neurotrophin family and a kind of secretory polypeptides.

A comprehensive literature search was conducted in the following databases: PubMed and Web of Science. The following search terms were used in various combinations: "NGF," "nerve growth factor," "ovarian steroidogenesis," "follicular development," "oocyte maturation," and "ovulation." Boolean operators (AND, OR) were applied to combine search terms (e.g., "NGF AND PCOS," "NGF AND follicular development").

NGF plays important roles in multiple reproductive physiological activities. Its ovarian effects are crucial for oocyte maturation, follicular assembly, early follicle development, ovulation and steroidogenesis. While the ovary is a major target, NGF's role extends to the broader regulation of the female reproductive system. In particular, the role of NGF in inducing ovulation by acting on the hypothalamus has garnered considerable scholarly attention. Although relatively few studies have examined the direct impact of NGF on hypothalamic gonadotrophin-releasing hormone neurons-the central regulators of the hypothalamic-pituitary-ovary (HPO) axis, extensive evidence demonstrates that NGF can cause an influence on the synthesis and release of follicle-stimulating hormone, luteinizing hormone and steroid hormones, which act downstream in the HPO axis.

Our review outlines the critical role of NGF in female reproductive physiology, with a particular focus on its modulatory influence on induced ovulation. Furthermore, in this review, we aim to provide a more comprehensive perspective on NGF's role in reproductive disorders, such as polycystic ovary syndrome, diminished ovarian reserve and endometriosis.