angiotensin

angiotensin
/an'jee oh ten"sin/, n. Biochem.
any of three oligopeptides occurring in plasma, an inactive form (angiotensin I) and two varieties (angiotensin II and angiotensin III) that elevate blood pressure and stimulate the adrenal cortex to secrete aldosterone.
[1960-65; prob. ANGIO(TONIN) + (HYPER)TENSIN, earlier names for the substances]

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      a peptide, one form of which, angiotensin II, causes constriction of blood vessels (blood vessel).

      There are three forms of angiotensin. Angiotensin I is produced by the action of renin (an enzyme produced by the kidneys (kidney)) on a protein called angiotensinogen, which is formed by the liver. Angiotensin I is transformed into angiotensin II in the blood by the action of angiotensin-converting enzyme (ACE). Angiotensin II acts directly on blood vessels, causing their constriction and thereby raising blood pressure. This substance also can cause vessel constriction through indirect mechanisms, such as by stimulating the release of the steroid hormone aldosterone and substances called catecholamines (catecholamine) from the adrenal glands (adrenal gland) and by blocking the reuptake of the hormone norepinephrine (epinephrine and norepinephrine) into neurons (neuron). Angiotensin III is a metabolite of angiotensin II and shares similar, though less potent, actions.

      Drugs that inhibit ACE, and thus block the conversion of angiotensin I to angiotensin II, are used to lower blood pressure in patients with hypertension. Blood pressure also can be lowered using drugs that are designed to block the receptors (receptor) to which angiotensin II must bind to exert its actions.

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Universalium. 2010.

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  • Angiotensin II — Kalottenmodell nach PDB  …   Deutsch Wikipedia

  • Angiotensin I — Kugelmodell nach PDB  …   Deutsch Wikipedia

  • angiotensin — [an΄jē ō ten′sin] n. [ ANGIO + TENS(ION) + IN1] a polypeptide that is a powerful vasopressor, formed in the blood by the action of renin on a plasma protein …   English World dictionary

  • Angiotensin — An|gio|ten|sin 〈n. 11; Pharm.〉 Gewebshormon, das aus acht Aminosäuren besteht u. blutdrucksteigernd wirkt [<grch. aggeion „Gefäß“ + lat. tendere „spannen“] * * * An|gi|o|ten|sin [griech. aggeĩon = Gefäß u. lat. tendere, tensum = spannen; ↑ in …   Universal-Lexikon

  • Angiotensin — A family of peptides (smaller than proteins) that act as vasoconstrictors to narrow blood vessels. * * * A family of peptides of known and similar sequence, with vasoconstrictive activity, produced by enzymatic action of renin upon… …   Medical dictionary

  • Angiotensin — Kalottenmodelle der Angiotensine I und II. Angiotensine, früher Angiotonine oder Hypertensine, sind eine zu den Gewebshormonen zählende Gruppe von Peptidhormonen, die durch enzymatische Spaltung aus Angiotensinogen der Leber gebildet werden. Dazu …   Deutsch Wikipedia

  • angiotensin II — A vasoactive octapeptide produced by the action of angiotensin converting enzyme on angiotensin I; produces stimulation of vascular smooth muscle, promotes aldosterone production, and stimulates the sympathetic nervous …   Medical dictionary

  • angiotensin — n. either of two peptides: angiotensin I or angiotensin II. Angiotensin I is derived, by the action of the enzyme renin, from a protein (alpha globulin) secreted by the liver into the bloodstream. As blood passes through the lungs, another enzyme …   The new mediacal dictionary

  • angiotensin — A peptide hormone. Angiotensinogen (renin substrate) is a 60 kD polypeptide released from the liver and cleaved in the circulation by renin to form the biologically inactive decapeptide angiotensin I. This is in turn cleaved to form active… …   Dictionary of molecular biology

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