Beyond GnRH, LH and FSH: the role of kisspeptin on hypothalalmic-pituitary gonadal (HPG) axis pathology and diagnostic consideration

Kisspeptin as a neuropeptide was established initially as regulator for gonadotropin-releasing hormone for pulse frequency and intensity. In the current review, initial search on PubMed was done with key word "Kisspeptin" with further filters to include reviews and trials from the last 10 years. Of the 313 articles shortlisted, 160(51%) dealt with kisspeptin pathology and diagnostic evaluation in various physiological conditions like puberty, while 57(18.2%) dealt with pathological conditions like hypogonadism, 53(17%) infertility, and 43(13.7%) with polycystic ovarian syndrome. This review explored existing data regarding understanding of the negative and positive influences on the kisspeptin hormone-release kinetics. It highlighted the recently identified ligands and pathways which could affect the gonadal steroids, including various metabolic alterations and environmental triggers. Also, the review highlighted the kisspepetin/G-protein coupled receptor-54 interaction which were influenced by neighbouring endocannabinoid system, Gamma aminobutyric acid (GABA)-ergic neuronal outputs and other chemical agents. It was also highlighted that the release of kisspepetin was identified as a group of neurons termed kisspeptin, neurokinin B, and dynorphin, or KNDy, in the arcuate nuclei. The data indicated the use of kisspepetin as a diagnostic marker for precocious puberty, puberty confirmation, hypogonadism, infertility and polycystic ovarian syndrome.