Somatostatin

Growth Hormone Inhibiting Hormone (or GHIH) somatotropin-releasing inhibitor hormone > is a 14 amino acid peptide hormone produced by the hypothalamus and the delta cells of the islets of Langerhans in the pancreas. It inhibits the production of growth hormone by the pituitary gland, it also has effects on the pancreas, where it inhibits the secretion of insulin and glucagon. It was the first recombinant protein produced in E. coli. This was a scientific success by being able to obtain a recombinant protein for the first time. Global formula: C₇₆H₁₀₄N₁₈O₁₉S₂

Functions

Inhibits the synthesis and/or secretion of growth hormone (GH, STH or somatotropin) by the adenohypophysis or anterior pituitary, so it is an anti-growth hormone. It also inhibits the hypothalamic-pituitary-thyroid axis, blocking the thyroid-stimulating hormone (TSH or thyrotropin) response to thyrotropin-releasing hormone or TRH. In addition, carcinoid tumors can express receptors for somatostatin and, moreover, it has been discovered that it has functions as a neurotransmitter in the central nervous system.

Other physiologic effects of pancreatic somatostatin include:

• Decrease in the digestion rate and absorption of nutrients by the gastrointestinal tract for subsequent use.
• Inhibition of the secretion of glucagon and insulin.
• Inhibition of gastric, duodenal and gallbladder motility, as it limits absorption through the digestive tract.
• Reduction of secretion of chloric acid, pepsin, gastrin, secretine, intestinal juice and pancreatic enzymes.
• Inhibition of the absorption of glucose and triglycerides through the intestinal mucosa.

Regulation

Somatostatin secretion is stimulated at the gastrointestinal level (by the gastrointestinal mucosa) and regulated by high levels of glucose, amino acids, glucagon, free fatty acids, and various gastrointestinal hormones. Its deficit or excess indirectly cause disorders in the metabolism of carbohydrates. It is also secreted by the hypothalamus and by other areas of the central nervous system (anterior paraventricular region, outer layer of the median eminence, subcommissural organ, pineal gland).

Isolation

Somatostatin was discovered by Roguer Guillemin in 1973, which he isolated from the brain, along with other hormones, which earned him the Nobel Prize in Physiology in 1977.

Chemical Structure

Somatostatin is a tetradecapeptide hormone with a disulfide bridge. It has the chemical structure H-Ala-Gly-Cys-Lys-Asn-Phe-Phe-Trp-Lys-Thr-Phe-Thr-Ser-Cys-OH.