Neuroendocrine mechanisms of stress-induced KNDy-GnRH pulse generator suppression: Linking HPA-axis activation to female reproductive dysfunction.

Chronic stress disrupts female reproductive function, but the central mechanisms linking stress exposure to altered gonadotropin-releasing hormone (GnRH) pulsatility remain incompletely defined. The arcuate kisspeptin/neurokinin B/dynorphin (KNDy) network is a core component of the GnRH pulse generator, yet it functions within an expanded regulatory system involving fast amino-acid neurotransmission, steroid feedback, nitric oxide signaling, glial communication, metabolic cues, and stress-responsive neuropeptides. This review synthesizes evidence showing how hypothalamic-pituitary-adrenal (HPA)-axis activation may suppress KNDy-GnRH output. Corticotropin-releasing hormone, glucocorticoids, gonadotropin-inhibitory hormone/RFamide-related peptide-3, glial inflammatory mediators, serotonergic input, and energy-sensitive neuropeptides may converge to impair GnRH pulse-generator function. We further discuss the relevance of these mechanisms to functional hypothalamic amenorrhea, stress-sensitive polycystic ovary syndrome (PCOS) phenotypes, and developmental versus adult stress exposure. Overall, stress-induced reproductive dysfunction is best understood as disrupted network-level neuroendocrine rhythm regulation.