Kisspeptin peptide is known to stimulate gonadotropin release in both men and women. It is commonly used in the preovulatory phase of the menstrual cycle in women.
Moreover, Kisspeptin is able to trigger hypothalamic GnRH neurons, thus regulating the oestrogen/testosterone (HPO) axis. It is also capable of inhibiting tumour metastasis. Kisspeptin was originally identified as a molecular switch for puberty and has since been shown to activate GnRH neurons during the early phases of pregnancy.
It has been observed that Kiss1 and its receptor, GPR54, are highly expressed in the hypothalamus of adult mice and rats. Specifically, Kiss1 mRNA is present in the arcuate nucleus of the hypothalamus, as well as in the anteroventral periventricular nucleus and amygdala. Interestingly, sex steroids are found to significantly upregulate Kiss1 expression in these brain areas.
Additionally, it has been observed that a number of conditions can lead to reduced GPR54 function. One example is a condition called ‘hypothalamic amenorrhoea’, which means that there is no oestrogen in the body. Kisspeptin has been found to stimulate the hypothalamus into releasing GnRH and it can therefore be used as an effective treatment for hypothalamic amenorrhoea.
Furthermore, it has been observed that kisspeptin is linked to melatonin. Melatonin is a natural sleep promoting hormone and it was found that people who slept under dark conditions had higher levels of melatonin in the blood, while those that slept under bright lights showed lower levels of this sleep-promoting compound in their blood.