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Somatostatin

المؤلف:  Norman, A. W., & Henry, H. L.

المصدر:  Hormones

الجزء والصفحة:  3rd edition , p136

2026-07-04

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Somatostatin is derived from a 116-amino-acid pre prosomatostatin that results in generation of soma tostatin-28 and somatostatin-14 peptides; both are biologically active. Somatostatin-28 is produced by enteroendocrine D cells which are specialized endocrine cells of the gastrointestinal tract. Somatostatin-14 has only 14 amino acids and one disulfide bond; it is produced by D cells present in the pancreas and the stomach. Although somatostatin was originally dis covered in the hypothalamus, it is also known to be produced by the δ-cells of the endocrine pancreas (see Figure 1A/B) and dispersed cells in the gastro intestinal tract. Somatostatin, when produced by the hypothalamus, is frequently termed growth hormone release-inhibiting hormone (GIF).

Fig1A. Schematic diagram of the cell types of a human pancreatic islet. (A) Illustration of the relative proportion of cells that secrete insulin (B cells), glucagon (A cells), somatostatin (D cells), pancreatic polypeptide (PP cells), and gastrin (G cells). The hormones are secreted and taken up into the pancreatic arteriole/capillary/venule system which ultimately delivers them to distal target organs (defined by the presence of their cognate receptor) where biological responses are then generated. The major biological functions of each hormone are listed in the green box.

Fig1B. Schematic diagram of a human pancreatic islet with respect to the relative proportion of cells. The hormone secreting cells are, respectively, insulin (pink), glucagon (light green), and somatostatin (blue). Note that the A cells which secrete glucagon are basically all located on the perimeter of the islet, while the few cells that secrete somatostatin are located adjacent to the A cells. Also shown are the capillaries (dark red) which are evenly spread throughout the islet. The capillaries are connected to arterioles, which in turn are connected to venules (see Figure 1A) which deliver the released insulin, glucagon, or somatostatin into the general circulatory system.