Why kisspeptin is such important for reproduction?

Recently discovered neuropeptide called kisspeptin is thought to be an essential gatekeeper in control of reproduction. Kisspeptin, the product of KiSS-1 gene and its G protein-coupled receptor GPR54 play a master role in the puberty period and fertility. This 54 amino acid peptide known also as metastatin, because of its metastasis suppression ability is also implicated in tumour biology. Kisspeptin/GPR54 system activates the hypothalamus-pituitary-ovarian axis. Its mechanism is not clearly understood. Kisspeptin influence is found above more at the level of hypothalamus but also at the pituitary and ovaries level. Kisspeptin can directly stimulate GnRH secretion from arcuate nucleus of hypothalamus. It is thought that kisspeptin plays an essential role in the metabolic regulation of fertility. In negative energy balance conditions an expression of KiSS-1 gene is decreased. Inactivating GPR54 mutations cause hypogonadotropic hypogonadism in humans. Simultaneously, mutations which increase GPR54 signalling are connected with gonadotropin-dependent premature puberty. Lately, possible therapeutic role of kisspeptin administration has been discussed. It was stated that kisspeptin might be used to manipulate the hypothalamic-pituitary-gonadal axis in humans. However, further studies are essential to reveal the exact mechanism and role of GPR54 agonists and antagonists applications. Moreover, the role of kisspeptin in the aspect of detection and treatment of specific cancers should be discovered.