insulin


insulin
/in"seuh lin, ins"yeuh-/, n.
1. Biochem. a polypeptide hormone, produced by the beta cells of the islets of Langerhans of the pancreas, that regulates the metabolism of glucose and other nutrients.
2. Pharm. any of several commercial preparations of this substance, each of which allows a particular rate of absorption into the system: genetically engineered or obtained from the pig or ox pancreas, and used in the treatment of diabetes to restore the normal ability of the body to utilize sugars and other carbohydrates.
[1910-15; INSUL(A) + -IN2]

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Polypeptide hormone (see peptide) that regulates blood glucose levels.

Secreted by the islets of Langerhans (see Langerhans, islets of) in the pancreas when blood glucose rises, as after a meal, it helps transfer the glucose into the body's cells to be oxidized (see oxidation-reduction) for energy or converted and stored as fatty acids or glycogen. When blood glucose falls, insulin secretion stops and the liver releases more glucose into the blood. Insulin has various related functions in the liver, muscles, and other tissues, controlling the balance of glucose with related compounds. Insulin-related disorders include diabetes mellitus and hypoglycemia. Frederick Banting and J.J.R. Macleod won a Nobel Prize in 1923 for discovering insulin, and Frederick Sanger won one in 1958 for determining its amino acid sequence.

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      hormone that regulates the level of sugar ( glucose) in the blood and is produced by the beta cells of the islets of Langerhans (Langerhans, islets of) in the pancreas. Insulin is secreted when the level of blood glucose rises—as after a meal. When the level of blood glucose falls, secretion of insulin stops, and the liver releases glucose into the blood.

      Insulin is a simple protein in which two polypeptide chains of amino acids are joined by disulfide linkages. Insulin helps transfer glucose into cells so that they can oxidize the glucose to produce energy for the body. In adipose (fat) tissue, insulin facilitates the storage of glucose and its conversion to fatty acids. Insulin also slows the breakdown of fatty acids. In muscle it promotes the uptake of amino acids for making proteins. In the liver it helps convert glucose into glycogen (the storage carbohydrate of animals) and it decreases gluconeogenesis (the formation of glucose from noncarbohydrate sources). The action of insulin is opposed by glucagon, another pancreatic hormone, and by epinephrine.

      Inadequate production of insulin is responsible for the condition called diabetes mellitus. Severe diabetics require periodic injections of insulin, which is extracted from the pancreas of pigs, sheep, and oxen. Insulin was first isolated as a pancreatic extract in 1921 by the Canadian scientists Sir Frederick G. Banting (Banting, Sir Frederick Grant) and Charles H. Best (Best, Charles H.). By the early 1980s certain strains of bacteria had been genetically modified to produce human insulin.

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Universalium. 2010.

Look at other dictionaries:

  • Insulin — Zwei Modelldarstellungen des Insulinmoleküls. Links das einfache Molekül (Monomer) als ein Kalottenmodell …   Deutsch Wikipedia

  • insulin — insulin. См. инсулин. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • Insulin — Insulin, in den B Zellen der Langerhans Inseln gebildetes Peptidhormon aus 51 Aminosäuren, die in zwei durch Disulfidbrücken miteinander verbundenen Peptidketten angeordnet sind. Es steigert die Durchlässigkeit der Zellmembranen für Glucose,… …   Deutsch wörterbuch der biologie

  • Insulin — blev første gang anvendt på et menneske den 11. Februar 1922. Det var de canadiske læger Banting og Best, der året før havde haft succes med at isolere hormonet for første gang. Siden er det blevet en uundværlig medicin for sukkersyge …   Danske encyklopædi

  • insulin — 1922 (earlier insuline, 1914), coined in English from L. insula island, so called because the hormone is secreted by the islets of Langerhans in the pancreas. Insuline was coined independently in French in 1909 …   Etymology dictionary

  • insulin — ► NOUN ▪ a hormone produced in the pancreas, which regulates glucose levels in the blood, and the lack of which causes diabetes. ORIGIN from Latin insula island (with reference to the islets of Langerhans in the pancreas) …   English terms dictionary

  • insulin — [in′sə lin] n. [< L insula, island (see ISLE) + IN1: in allusion to the islets of Langerhans] 1. a protein hormone secreted by the islets of Langerhans, in the pancreas, which helps the body use sugar and other carbohydrates 2. a preparation… …   English World dictionary

  • Insulin — This article is about the insulin protein. For uses of insulin in treating diabetes, see insulin therapy. Not to be confused with inulin. Insulin Computer generated image of six insulin molecules assembled in a hexamer, highlighting the threefold …   Wikipedia

  • insulin — A polypeptide hormone, secreted by beta cells in the islets of Langerhans, that promotes glucose utilization, protein synthesis, and the formation and storage of neutral lipids; available in a variety of preparations including genetically… …   Medical dictionary

  • Insulin — In|su|lin 〈n. 11; unz.〉 vom Inselorgan der Bauchspeicheldrüse gebildetes Hormon, das den Blutzuckerspiegel senkt [zu lat. insula „Insel“, nach den langerhansschen Inseln] * * * In|su|lin [lat. insula = Insel (wegen der Bildung in den Langerhans… …   Universal-Lexikon


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