Research Overview
Two origins, one peptide
KISS1 was first characterised as a metastasis-suppressor gene in melanoma cell lines, and its product was named metastin for that reason. Its reproductive function surfaced independently when investigators found that inactivating mutations in the orphan receptor GPR54 caused failure of pubertal development. Both literatures remain active, and Kisspeptin-10 serves as the standard tool compound in each.
Position in the HPG axis
Kisspeptin neurons form two distinct populations. Those in the arcuate nucleus co-express neurokinin B and dynorphin — the so-called KNDy neurons — and are implicated in generating the pulsatile rhythm that drives GnRH release. Those in the anteroventral periventricular nucleus mediate positive oestrogen feedback in models of the preovulatory surge. Because GnRH neurons themselves express KISS1R densely, kisspeptin sits directly upstream of the entire cascade to LH, FSH and gonadal steroid output.
- Pulsatile versus continuous stimulation and downstream receptor behaviour
- Steroid feedback integration in arcuate and AVPV populations
- Puberty-onset timing in animal models
- Comparisons with GnRH agonists such as gonadorelin and triptorelin, which act one step lower in the axis
Structural requirements
Structure–activity work shows that the C-terminal decapeptide carries essentially all of the receptor activity present in the 54-residue parent, and that the terminal amide is indispensable — the free acid loses potency dramatically. The RFamide motif that gives the family its name is the key recognition element. Kisspeptin-10 has a short circulating half-life relative to kisspeptin-54, a difference that itself is a common experimental variable.
