somatostatin


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Related to somatostatin: Octreotide

Somatostatin

A naturally occurring regulatory peptide that carries out numerous functions in the human body, including the inhibition of growth hormone secretion from the anterior pituitary gland. Somatostatin consists of 14 amino acids; two cysteine residues are joined by a disulfide bond so that the peptide forms a ring structure. A larger variant of this peptide, called somatostatin-28, is produced in some cells and has an additional 14 amino acids attached at the amino-terminal end of normal somatostatin (somatostatin-14).

Somatostatin acts primarily as a negative regulator of a variety of different cell types, blocking processes such as cell secretion, cell growth, and smooth muscle contraction. It is secreted from the hypothalamus into the portal circulation and travels to the anterior pituitary gland, where it inhibits the production and release of both growth hormone and thyroid-stimulating hormone. Many tissues other than the hypothalamus contain somatostatin, suggesting that this peptide has numerous roles.

Each of the functions of somatostatin is initiated by the binding of the peptide to one or more of five different cell-surface receptor proteins, thereby activating one or more intracellular G-proteins and initiating biochemical signaling pathways within the cell. See Signal transduction

Analogs of somatostatin have been synthesized that are smaller, more potent, longer-lasting, and more specific in their biological effects than natural somatostatin. Some of these analogs have become useful as drugs. See Endocrine system (vertebrate), Hormone, Neurosecretion, Pituitary gland

somatostatin

[¦sō·məd·ə′stat·ən]
(biochemistry)
A peptide secreted by the hypothalamus which acts primarily to inhibit the release of growth hormone from the anterior pituitary.
References in periodicals archive ?
Orlando, "Somatostatin receptors in non-endocrine tumours," Digestive and Liver Disease, vol.
Radioactive Somatostatin Analogs for Imaging and Therapy
68Ga-DOTA-Tyr3-octreotide PET in neuroendocrine tumours: comparison with somatostatin receptor scintigraphy and CT.
Construction and evaluation of novel plasmid DNA encoding somatostatin fused to a tissue plasminogen activator (tPA) in mice.
Short-term effects of somatostatin analogue (SMS 201-995) on left ventricular function in healthy persons: a scintigraphic study.
Somatostatin receptors: (SSTRs) are a group of G protein-coupled membrane-bound receptors that SST and its long-acting analogues interact with to trigger their biologic effects.
Somatostatin receptor 2a is a more sensitive diagnostic marker of meningioma than epithelial membrane antigen.
Atypical presentation of chronic pancreatic fistula: a case successfully managed with long-acting somatostatin. Turk J Gastroenterol 2003; 14: 200-3.
The choice to target somatostatin receptors is based on the analysis of expression levels of SSTRs in relatively small groups of human corticotroph pituitary adenomas ranging from 1 to 13 cases using RT-PCR [17-22] and the experience that had been gained with inhibitory substances in other endocrine tumors and diseases [21].
Somatostatin analogues such as octreotide have been reported to improve the symptoms of carcinoid syndrome [3].
Treatment options of AUGIB were collected as follows: endoscopic therapy (i.e., band ligation, sclerotherapy, and histoacryl), Sengstaken Blackmore tube, somatostatin and/or octreotide, blood transfusion, proton pump inhibitors (PPIs), and surgery.
In the human antral gastric mucosa, apart from the well-known endocrine cell secreting gastrin (G), somatostatin (D) and serotonin (EC), an unknown secretory product of D(1) cells and P cells has also been identified [18].

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