Somatostatin-14 is a natural cyclic peptide hormone derived from the preprohormone, somatostatin. It is a somatostatin (SST) receptor agonist that binds to SST1, SST2, SST3, SST4, and SST5 (IC50s = 0.22, 0.10, 0.28, 1.23, and 0.30 nM, respectively, in CCL39 cells expressing human recombinant receptors). It inhibits cAMP accumulation induced by forskolin in CCL39 cells expressing human recombinant SST1, SST2, SST3, SST4, and SST5 (EC50s = 6.16, 4.37, 17.38, 2.95, and 4.67 nM, respectively). Somatostatin-14 inhibits the release of growth hormone, prolactin, thyrotropin, glucagon, and insulin, as well as other signaling molecules.