Somatostatin-14 (SST-14) is a small cyclic peptide hormone secreted by hypothalamus. SST-14 has several roles including inhibiting the release of several hormones such as; growth hormone (GH), gastrin and gastric acid, insulin and glucagon and the regulation of amyloid beta-42. In the brain somatostatin increases body temperature and influences visceral functions (e.g. increased blood pressure, decreased heart rate, prevents sympathetically mediated hyperglycemia and stimulates gastric acid secretion).

Somatostatin is also present in an N-terminally extended form, somatostatin-28. In mammals, both somatostatin-14 and 28 originate from the prohormone, prosomatostatin, which is generated after removal of a 24 amino acid signal sequence from the 116 amino acids precursor, preprosomatostatin. Somatostatin-14 and 28 bind with similar affinity to five distinct somatostatin receptor subtypes, sst1 to sst5. These receptors belong to the G-protein coupled seven transmembrane domain receptor family and are related to the urotensin II receptors.