Quick answer: Kisspeptin is a family of peptides (10, 13, 14 or 54 residues) cut from the product of the KISS1 gene. Two 2001 papers showed they activate the receptor GPR54, and later genetic and animal work placed the pair near the top of the signaling chain for GnRH. V8 does not sell kisspeptin; this page is research background only.
A gene found by one name and a peptide family named by another
Kisspeptin is the name for a small family of peptides that are all cut from the same precursor protein. The gene that encodes the precursor, KISS1, was first described in the 1990s in the context of cancer biology, where it was reported to suppress the spread of tumor cells in a melanoma model. That is why the early literature calls it the KiSS-1 metastasis suppressor gene. The peptides it encodes were not identified as signaling molecules until 2001, when two groups working independently reported that the gene product is the natural partner of a previously orphaned receptor.
This guide explains what kisspeptin is, how the field moved from a cancer gene to reproductive signaling, and what a laboratory should check before buying any peptide from this family. It is background for laboratory research use only. V8 Peptides does not sell kisspeptin, and nothing here describes a use in people or animals. For other explainers in this style, see is NAD+ a peptide and what is KPV.
The precursor and the peptides cut from it
The KISS1 gene is translated into a precursor of 145 amino acids. Enzymes in the cell cleave it into a longer product of 54 residues, called kisspeptin-54 (also written metastin), and shorter fragments. The commonly studied shorter forms are kisspeptin-14, kisspeptin-13 and kisspeptin-10. All of them end in the same short stretch, which finishes with an amidated phenylalanine and an arginine just before it (an RF-amide motif). The region that holds the shared ending is what binds the receptor, so the shortest form, kisspeptin-10, is the smallest piece that keeps receptor activity in the original assays.
Because several lengths exist, a product label that says only "kisspeptin" is incomplete. Kisspeptin-10 is a 10-residue peptide of roughly 1.3 kDa. Kisspeptin-54 is more than four times larger. They are different reagents with different molecular weights, different handling properties and different analytical signatures, and published results for one should not be read as results for another.
Side-by-side comparison
| Name | Length | What it is |
|---|---|---|
| KISS1 gene | Encodes a 145-residue precursor | First described in cancer biology as a metastasis suppressor |
| Kisspeptin-54 (metastin) | 54 residues | Longest product cut from the precursor |
| Kisspeptin-14 / -13 | 14 or 13 residues | Shorter products with the same C-terminal motif |
| Kisspeptin-10 | 10 residues, about 1.3 kDa | Shortest form that keeps receptor activity in early assays |
| GPR54 / KISS1R | G protein-coupled receptor | Identified as the kisspeptin receptor in 2001 |
| GnRH | Hypothalamic hormone | Reported in mice to be released after kisspeptin acts at GPR54 |
How the receptor was identified
The receptor is called GPR54, and now more often KISS1R. It is a G protein-coupled receptor that had been cloned earlier without a known partner. In 2001, Kotani and colleagues and Ohtaki and colleagues each reported that peptides derived from the KISS1 gene activate this receptor in cell-based assays. These two papers are the starting point of almost every later study and are the right first references for anyone entering the area.
Receptor activation in these assays was measured through signaling events inside the cell, such as calcium release. Those are cell-culture readouts. They show that the peptide and receptor interact, and they say nothing by themselves about what happens in an organism.
Why reproductive biologists took notice
In 2003, two groups reported that people carrying inactivating changes in the GPR54 gene had a condition in which the hormonal axis that controls reproductive development failed to switch on normally. De Roux and colleagues described this in a family study and Seminara and colleagues described it in a separate set of families, and the second paper also reported on mice lacking the receptor. These are human-genetics and knockout-model findings. They placed the kisspeptin and receptor pair near the top of the signaling chain that governs gonadotropin-releasing hormone (GnRH), the hypothalamic hormone at the head of that axis.
In 2005, Messager and colleagues reported in mice that kisspeptin acted through GPR54 to trigger release of GnRH, and that the response was absent in animals without the receptor. A comprehensive review by Pinilla and colleagues in 2012 collects the anatomy and physiology across species. Readers who want the full picture should start there rather than from secondary web summaries.
What the evidence does and does not cover
The strongest parts of this literature are the identification of the gene, the peptides and the receptor, the genetic findings, and animal studies of the signaling pathway. Those are the claims that rest on multiple independent groups and on genetic evidence.
Material that is thinner includes the long list of other roles that have been suggested for the system, and any statement that goes beyond the species and conditions in a given paper. It is also worth remembering that a cancer-suppressor label from the earliest work does not carry over to the signaling role described later, and that the original cancer-biology reports and the reproductive-biology reports address different questions.
A neutral rule for reading any article on this topic: note the species, the form of kisspeptin that was used (10, 13, 14 or 54 residues), and whether the readout was a cell assay, a hormone measurement in animals or a human genetic study.
What a certificate should show for a kisspeptin reagent
Look for the exact form named on the certificate, with the sequence or the number of residues, and a measured mass next to the expected value. A kisspeptin-10 result should sit near 1.3 kDa; a result near 6 kDa corresponds to the 54-residue form. For background on reading these documents, see understanding HPLC purity, HPLC vs. mass spectrometry and how to read a COA.
The C-terminal amide is a place to look closely. The shared ending of the family is amidated, and a product made as a free acid instead has a mass about one unit higher and may behave differently at the receptor. A mass spectrum with the right resolution can tell these apart; a bare purity percentage cannot. The longer forms also contain residues that are prone to oxidation and deamidation during synthesis and storage, so read the chromatogram for shoulders next to the main peak.
For cell-based work, endotoxin and sterility results matter as much as purity, since endotoxin alone can trigger responses in culture. More buyer-side guidance is in choosing a peptide supplier and red flags when buying research peptides.
Handling and record keeping
Keep lyophilized peptide cold, dry and protected from light, and write the date on the vial when it is first opened. Plan aliquots before opening so a vial is not repeatedly handled. General guidance on how long solutions hold up is in how long reconstituted peptides last, and what an ordinary versus a worrying vial looks like is in vial appearance: what is normal.
In the notebook, record the exact form (for example kisspeptin-10), sequence, lot, supplier, certificate date and storage conditions, so a later reader can tie any result to a defined reagent.
Frequently asked questions
What is kisspeptin?
A family of peptides cut from the product of the KISS1 gene. They signal through the receptor GPR54, also called KISS1R.
Why is it called metastin?
The gene was first reported as a suppressor of metastasis in a melanoma model, and the 54-residue product was named metastin after that finding.
What is the difference between kisspeptin-10 and kisspeptin-54?
They are different lengths of the same family. Kisspeptin-10 has 10 residues and kisspeptin-54 has 54, so mass, handling and analytical signature all differ.
Which papers identified the receptor?
Kotani and colleagues in the Journal of Biological Chemistry and Ohtaki and colleagues in Nature, both published in 2001.
Is kisspeptin research mostly in cells or in animals?
Both, plus human genetic studies. The receptor identification used cell assays, the signaling work used animals, and the 2003 reports studied families with receptor changes.
Why does the C-terminal amide matter?
The shared ending of the family is amidated. A product synthesized as a free acid has a slightly different mass and may behave differently, which a mass spectrum can reveal.
Does V8 sell kisspeptin?
No. This page is background only and is not a product listing.
Can a purity percentage prove which kisspeptin form I have?
No. Only a measured mass next to the expected mass, together with the sequence, shows the form.
Does this article describe a use in people?
No. It summarizes published laboratory, genetic and cell-culture research and analytical practice. Nothing here is a recommendation for use in people or animals.
What should I record for each vial of any research peptide?
The exact compound name, sequence, lot identifier, certificate date, supplier, storage conditions and the date the vial was opened.
References
- Kotani M, Detheux M, Vandenbogaerde A, et al. The metastasis suppressor gene KiSS-1 encodes kisspeptins, the natural ligands of the orphan G protein-coupled receptor GPR54. J Biol Chem. 2001;276(37):34631-34636.
- Ohtaki T, Shintani Y, Honda S, et al. Metastasis suppressor gene KiSS-1 encodes peptide ligand of a G-protein-coupled receptor. Nature. 2001;411(6837):613-617.
- de Roux N, Genin E, Carel JC, et al. Hypogonadotropic hypogonadism due to loss of function of the KiSS1-derived peptide receptor GPR54. Proc Natl Acad Sci U S A. 2003;100(19):10972-10976.
- Seminara SB, Messager S, Chatzidaki EE, et al. The GPR54 gene as a regulator of puberty. N Engl J Med. 2003;349(17):1614-1627.
- Messager S, Chatzidaki EE, Ma D, et al. Kisspeptin directly stimulates gonadotropin-releasing hormone release via G protein-coupled receptor 54. Proc Natl Acad Sci U S A. 2005;102(5):1761-1766.
- Pinilla L, Aguilar E, Dieguez C, Millar RP, Tena-Sempere M. Kisspeptins and reproduction: physiological roles and regulatory mechanisms. Physiol Rev. 2012;92(3):1235-1316.