Kisspeptin is a neuroendocrine peptide hormone that serves as a central regulator of reproductive endocrine signaling. Its primary function is activation of gonadotropin-releasing hormone neurons within the hypothalamus. Through this action, kisspeptin controls release of luteinizing hormone and follicle-stimulating hormone from the pituitary gland, thereby regulating gonadal steroid production, gamete development, fertility, and reproductive cycling.
Kisspeptin signaling is essential for initiation of puberty, maintenance of reproductive function, ovulatory cycling, and coordination between nutritional status and fertility. The hormone integrates information related to energy reserves, metabolic status, circadian timing, and gonadal feedback to regulate reproductive endocrine output. Kisspeptin neurons participate in generation of pulsatile GnRH release patterns required for normal reproductive physiology.
Kisspeptin is produced mainly by specialized hypothalamic neurons, particularly within the arcuate nucleus and anteroventral periventricular regions. The hormone is encoded by the KISS1 gene and synthesized as precursor peptides that are processed into active kisspeptin fragments. These peptides signal through the KISS1 receptor, also known as GPR54, which is highly expressed on GnRH neurons.
Some kisspeptin production also occurs in placenta, pancreas, liver, gonads, and additional tissues, although hypothalamic production is most important for endocrine reproductive regulation. Kisspeptin neurons often coexpress neurokinin B and dynorphin, forming integrated neuroendocrine pulse-generating systems involved in reproductive timing and hormonal rhythmicity.
Kisspeptin production is regulated by sex steroids, nutritional status, leptin signaling, stress pathways, circadian rhythms, developmental timing, and reproductive feedback systems. Estradiol strongly influences kisspeptin neurons, suppressing some hypothalamic populations while stimulating others involved in ovulatory signaling. Testosterone and progesterone also regulate kisspeptin activity depending on sex and reproductive phase.
Low energy availability, excessive metabolic stress, inflammatory signaling, or impaired leptin signaling can suppress kisspeptin release and reduce reproductive hormone output. Kisspeptin signaling activates phospholipase C, intracellular calcium pathways, and depolarization mechanisms within GnRH neurons. Through these systems, kisspeptin functions as a major reproductive gatekeeper that integrates endocrine, metabolic, and developmental information to coordinate fertility-related hormonal signaling.
Kisspeptin regulates GnRH release and coordinates reproductive hormone signaling from hypothalamus to ovaries and testes.
