Renin-angiotensin system: Difference between revisions

From Citizendium
Jump to navigation Jump to search
imported>Robert Badgett
imported>Robert Badgett
Line 5: Line 5:
{{related}}
{{related}}
"[[Renin]], an enzyme produced in the [[kidney]], acts on angiotensinogen, an alpha-2 globulin produced by the [[liver]], forming [[angiotensin]] I. [[angiotensin-converting enzyme]], contained in the [[lung]], acts on [[angiotensin]] I in the plasma converting it to [[angiotensin]] II, an extremely powerful vasoconstrictor. [[Angiotensin]] II causes contraction of the arteriolar and renal vascular smooth muscle, leading to retention of salt and water in the [[kidney]] and increased arterial [[blood pressure]]. In addition, [[angiotensin]] II stimulates the release of [[aldosterone]] from the adrenal cortex, which in turn also increases salt and water retention in the [[kidney]]. Angiotensin-converting enzyme also breaks down bradykinin, a powerful vasodilator and component of the kallikrein-kinin system."<ref name="MeSH-RAS"/>
"[[Renin]], an enzyme produced in the [[kidney]], acts on angiotensinogen, an alpha-2 globulin produced by the [[liver]], forming [[angiotensin]] I. [[angiotensin-converting enzyme]], contained in the [[lung]], acts on [[angiotensin]] I in the plasma converting it to [[angiotensin]] II, an extremely powerful vasoconstrictor. [[Angiotensin]] II causes contraction of the arteriolar and renal vascular smooth muscle, leading to retention of salt and water in the [[kidney]] and increased arterial [[blood pressure]]. In addition, [[angiotensin]] II stimulates the release of [[aldosterone]] from the adrenal cortex, which in turn also increases salt and water retention in the [[kidney]]. Angiotensin-converting enzyme also breaks down bradykinin, a powerful vasodilator and component of the kallikrein-kinin system."<ref name="MeSH-RAS"/>
Angiotensin-converting enzyme 2 is a newly recognized component of the renin-angiotensin system.<ref name="pmid12456857">{{cite journal |author=Boehm M, Nabel EG |title=Angiotensin-converting enzyme 2--a new cardiac regulator |journal=N. Engl. J. Med. |volume=347 |issue=22 |pages=1795–7 |year=2002 |month=November |pmid=12456857 |doi=10.1056/NEJMcibr022472 |url=http://content.nejm.org/cgi/pmidlookup?view=short&pmid=12456857&promo=ONFLNS19 |issn=}}</ref>


==Clinical significance==
==Clinical significance==

Revision as of 13:59, 15 June 2008

This article is a stub and thus not approved.
Main Article
Discussion
Related Articles  [?]
Bibliography  [?]
External Links  [?]
Citable Version  [?]
 
This editable Main Article is under development and subject to a disclaimer.

The renin-angiotensin system is a "blood pressure regulating system of interacting components that include renin; angiotensinogen; angiotensin converting enzyme; angiotensin I; angiotensin II; and angiotensinase."[1]

Components and physiology

For links to more information, see: Renin-angiotensin system: Subtopics


"Renin, an enzyme produced in the kidney, acts on angiotensinogen, an alpha-2 globulin produced by the liver, forming angiotensin I. angiotensin-converting enzyme, contained in the lung, acts on angiotensin I in the plasma converting it to angiotensin II, an extremely powerful vasoconstrictor. Angiotensin II causes contraction of the arteriolar and renal vascular smooth muscle, leading to retention of salt and water in the kidney and increased arterial blood pressure. In addition, angiotensin II stimulates the release of aldosterone from the adrenal cortex, which in turn also increases salt and water retention in the kidney. Angiotensin-converting enzyme also breaks down bradykinin, a powerful vasodilator and component of the kallikrein-kinin system."[1]

Angiotensin-converting enzyme 2 is a newly recognized component of the renin-angiotensin system.[2]

Clinical significance

Several classes of medications affect the renin-angiotensin system.

Regarding combining these medications for a synergistic effect, an initial randomized controlled trial suggests benefit for combining aliskiren is an oral direct renin inhibitor with losartan, an angiotensin II receptor antagonist.[3] Randomized controlled trials have investigated the use of the latter two classes together for a synergistic effect, but have found increased adverse effects with no added benefit from their combination.[4]

Direct renin inhibitors

Aliskiren is an oral direct renin inhibitor that according to a randomized controlled trial may have "renoprotective effects that are independent of its blood-pressure-lowering effect in patients with hypertension, type 2 diabetes, and nephropathy."[3]

Angiotensin-converting enzyme inhibitors

For more information, see: Angiotensin-converting enzyme inhibitor.

Angiotensin-converting enzyme inhibitors are medications used for the treatment of hypertension and heart failure.

Angiotensin II receptor antagonists

For more information, see: Angiotensin II receptor antagonist.

Angiotensin II receptor antagonists are medications that antagonize the angiotensin II type 1 receptor and are used for the treatment of hypertension.

References

  1. 1.0 1.1 Anonymous (2024), Renin-angiotensin system (English). Medical Subject Headings. U.S. National Library of Medicine.
  2. Boehm M, Nabel EG (November 2002). "Angiotensin-converting enzyme 2--a new cardiac regulator". N. Engl. J. Med. 347 (22): 1795–7. DOI:10.1056/NEJMcibr022472. PMID 12456857. Research Blogging.
  3. 3.0 3.1 Parving HH, Persson F, Lewis JB, Lewis EJ, Hollenberg NK (June 2008). "Aliskiren combined with losartan in type 2 diabetes and nephropathy". N. Engl. J. Med. 358 (23): 2433–46. DOI:10.1056/NEJMoa0708379. PMID 18525041. Research Blogging.
  4. McMurray JJ (April 2008). "ACE inhibitors in cardiovascular disease--unbeatable?". N. Engl. J. Med. 358 (15): 1615–6. DOI:10.1056/NEJMe0801925. PMID 18378521. Research Blogging.