Metastin (45-54) is a 10 amino acid peptide that corresponds to the bioactive C-terminal 45-54 amino acids of metastin, a metastasis suppressor gene product. It acts as a potent agonist of GPR54 (OT7T175, AXOR12), with approximately 8-fold higher binding affinity than metastin (Ki values of 0.042 and 0.34 nM, respectively, for displacement of metastin (40-54)). Metastin (45-54) induces calcium mobilization in GPR54-transfected cells (EC50 = 0.18-1.1 nM). It inhibits the migration of GPR54-transfected CHO cells at concentrations of 10-100 nM, equaling the potency of full length metastin.

Metastin is also known as kisspeptin 1 (KISS1). It is encoded by KISS1 gene, that is mapped to human chromosome 1q32. Metastin is a tumor suppressor protein, made up of 145 amino acids. The protein fragments contain RFamide motif at the C- terminal end. The encoded protein is expressed in the human hypothalamus, gonads, placenta, liver and pancreas. This novel?peptide?is mainly isolated from the human placenta.

Metastin (45-54) amide has been used in progesterone release experiments from MA-10 cells. It has also been used to induce gonadal differentiation in clownfish.

Metastin (45-54) is a potent and selective agonist of AXOR12 and hOT7T175.