Kisspeptin-10: KISS1R Signalling and the Desensitisation Problem

Two origins, one gene

KISS1 was first identified as a metastasis suppressor gene, and the peptide was named metastin. Kisspeptin-10 is also written as metastin 45-54. The reproductive role was discovered later, when loss-of-function mutations in GPR54 were found to cause hypogonadotropic hypogonadism.

Both literatures remain active and largely separate. Ulasov et al. (Cancer Metastasis Rev, 2019) cover KISS1 in breast cancer progression and autophagy. Tena-Sempere (Hum Reprod Update, 2006) covers the reproductive axis. A reader searching this compound will encounter both and should not assume they are describing the same phenomenon.

Signalling and the pulsatility requirement

KISS1R is a Gq-coupled receptor. Activation in GnRH neurons drives phospholipase C, inositol trisphosphate and calcium mobilisation, producing GnRH release and downstream gonadotropin secretion.

Seminara et al. (Endocrinology, 2006) is the paper that matters most for experimental design. Continuous infusion of human metastin 45-54 in the juvenile male rhesus monkey desensitised the GPR54-induced GnRH release. Continuous exposure does not produce a sustained effect; it abolishes the response.

This is a mechanistic property of the receptor, not a dosing preference. Any protocol using continuous administration and expecting sustained axis stimulation is working against a published and specific result.

Activity outside the reproductive axis

Li et al. (Nat Commun, 2024) report that kisspeptin-10 binding to Gpr54 in osteoclasts prevents bone loss through Dusp18-mediated dephosphorylation of Src, with an author correction published the same year. This is among the better-characterised non-reproductive mechanisms.

Son et al. (Sci Rep, 2018) report stimulation of osteoblast differentiation through GPR54-mediated BMP2 regulation, which complements the osteoclast finding from the other side of bone remodelling.

Simon et al. (Int J Mol Sci, 2023) report mitigation of alpha-synuclein-mediated mitochondrial apoptosis in SH-SY5Y-derived neurons in a kisspeptin receptor-independent manner. Receptor-independent findings are worth flagging explicitly, because they cannot be interpreted through the KISS1R framework that governs the rest of the literature.

Terse et al. (Int J Toxicol, 2021) provide a fourteen-day repeat-dose safety evaluation in dog, which is one of the few formal toxicology studies available for any compound in this catalogue.