Kisspeptin is a peptide hormone that is found in the brain. It has many actions including influencing hormone signaling during puberty and reproduction, altering mood, promoting angiogenesis (blood vessel growth) and regulating kidney function. It is also known to suppress tumour growth and metastasis (spread).
Studies suggest that kisspeptin signalling occurs outside the hypothalamus extending to key limbic structures which orchestrate emotions such as the amygdala, hippocampus and cingulate as well as paralimbic structures that feed into these areas such as the stria terminalis, putamen and nucleus accumbens. Kisspeptin has been shown to project from these areas via the amygdala to GnRH neurones in the preoptic area of the brain thereby connecting these regions.
Another significant effect of kisspeptin is its ability to increase ovulation (release of an egg from the ovary during the menstrual cycle). This increased ovulation is needed for fertility treatment such as in vitro fertilisation where eggs are collected from a woman and then artificially fertilised in the laboratory. Kisspeptin has been shown to stimulate this process without causing a dangerous side-effect of current fertility treatment called ovulation hyperstimulation syndrome.
The most important effect of kisspeptin appears to be its ability to stimulate gonadotropin releasing hormone secretion. This is of particular interest as low levels of this hormone can lead to a condition called ‘hypothalamic amenorrhoea’ in women which is characterized by the absence of periods. This is due to a reduction in the normal function of the hypothalamus resulting in reduced hormone secretion by it.