Kisspeptin peptide is of great scientific interest as it plays an important role in hormonal signalling during puberty and reproduction. It also influences mood and behaviour, promotes angiogenesis (growth of new blood vessels) and regulates kidney function.
A central part of the hypothalamic-pituitary-gonadal axis, KP is a key regulator of gonadotropin-releasing hormone (GnRH) release and is implicated in the preovulatory surge of LH. Kisspeptin also appears to be involved in the control of luteinising hormone secretion and sex steroid production.
In the brain, kisspeptin neurones are positioned at the apex of the HPG axis. These are surrounded by a diverse array of neuronal systems including paralimbic, limbic and dopaminergic neurons.
Within the amygdala, olfactory stimulation activates the kisspeptin neurones which in turn relay a message to GnRH-neurones in the preoptic area of the brain. This induction of GnRH signalling is crucial for olfactory stimuli to initiate social and emotional responses such as audition, fear, anxiety and mood, with the latter implicated in the development of sexual arousal.
Interestingly, it has been found that the levels of these peptides are drastically different in mice exposed to daylight compared with those kept in darkness. This is thought to have implications for the ability of the peptides to suppress tumor growth and metastasis in tumour cells.
Kisspeptin is the cleavage product of the kiss-1 gene and has been shown to suppress metastatic cancer in mouse models. However, the exact nature of this interaction remains unclear.