GHRH and reproductive systems: Mechanisms, functions, and clinical implications

Growth hormone-releasing hormone (GHRH) has classically been considered a regulatory neuropeptide of the hypothalamic-pituitary system, which mediates its anabolic effects through hepatic GH/IGF-I axis. However, during the last decades it has been demonstrated that this key regulatory hormone may be produced in numerous peripheral tissues outside the central nervous system, participating in fundamental physiological functions through a complex balance between its purely endocrine action, and the recently local (autocrine/paracrine) discovered role. Among peripheral sites, its presence in the male and female reproductive systems stands out. In this review, we will first explore the role of the GHRH/GHRH-R hormone axis as a central player in the gonadal function; then, we will discuss available information regarding the presence of GHRH/GHRH-R and the potential physiological roles in reproductive systems of various species; and finally, we will address how reproductive system-related disorders-such as infertility problems, endometriosis, or tumor pathologies (including prostate, or ovarian cancer)-could benefit from hormonal interventions related to the manipulation of the GHRH axis.