Somatostatin

A hormone widely distributed throughout the body, especially in the hypothalamus and pancreas, that acts as an important regulator of endocrine and nervous system function by inhibiting the secretion of several other hormones such as growth hormone, insulin, and gastrin. It exerts its biologic actions by binding to specific high-affinity receptors on the cell surface. The gene encoding somatostatin is termed SST and is on chromosome 3 in region 3q28.

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A tetradecapeptide capable of inhibiting the release of somatotropin by the anterior lobe of the pituitary gland; s. has a short half-life; it also inhibits the release of insulin and gastrin. SYN: growth hormone-inhibiting hormone, somatotropin release-inhibiting factor, somatotropin release-inhibiting hormone. [somatotropin + G. stasis, a standing still, + -in]

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so·mato·stat·in sō-.mat-ə-'stat-ən n a polypeptide neurohormone that is found esp. in the hypothalamus, is composed of a chain of 14 amino acid residues, and inhibits the secretion of several other hormones (as growth hormone, insulin, and gastrin)

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a hormone, produced by the hypothalamus and some extraneural tissues, including the gastrointestinal tract and pancreas (see islets of Langerhans), that inhibits growth hormone (somatotrophin) release by the pituitary gland. Both growth-hormone releasing hormone and somatostatin are controlled by complex neural mechanisms related to sleep rhythms, stress, neurotransmitters, blood glucose, and exercise. Its inhibitory effect on gastrointestinal secretions is used to reduce flow from fistula from the pancreas or bowel to the body surface. Its effect on reducing abdominal blood flow is used to reduce bleeding from oesophageal varices.

Somatostatin analogues are used to treat acromegaly, caused by overproduction of growth hormone, and to relieve the symptoms caused by hormone-secreting neuroendocrine tumours. They include lanreotide (Somatuline) and octreotide (Sandostatin), which are administered by injection.

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so·ma·to·stat·in (SS) (so″mə-to-statґin) [somatotropin + -statin] any of several cyclic tetradecapeptides elaborated primarily by the median eminence of the hypothalamus and by the delta cells of the pancreatic islets; they inhibit release of growth hormone, thyrotropin, and corticotropin by the adenohypophysis, of insulin and glucagon by the pancreas, of gastrin by the gastric mucosa, of secretin by the intestinal mucosa, and of renin by the kidney. Called also growth hormone release–inhibiting hormone and somatotropin release–inhibiting hormone.