| The renin-angiotensin system. Normal physiology and changes in older hypertensives. | |
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MedLine Citation:
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PMID: 2666488 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The long-term effects of angiotensin (ANGII) on arterial pressure regulation appear to be closely linked to volume homeostasis, via the renal-pressure natriuresis mechanism, both in normal humans and in older hypertensives. In response to disturbances such as increased sodium intake, suppression of ANGII and aldosterone formation greatly amplifies the effectiveness of the pressure natriuresis mechanism, thereby preventing large increases in body fluid volumes and minimizing the rise in blood pressure needed to maintain sodium balance. When ANGII levels are inappropriately elevated, the antinatriuretic effects of ANGII cause increased arterial pressure, which then serves to maintain sodium and water balance via the pressure natriuresis mechanism. The primary intrarenal and extrarenal mechanisms by which ANGII controls renal excretion and arterial pressure include: (1) a direct effect of ANGII on tubular sodium transport; (2) a preferential constrictor action of ANGII on efferent arterioles, which increases sodium reabsorption by altering peritubular capillary physical forces (efferent arteriolar constriction also prevents excessive decreases in glomerular filtration rate when renal perfusion is compromised, such as in renal artery stenosis); and (3) extrarenal effects of ANGII, including stimulation of aldosterone secretion. Current evidence suggests that the direct effects of ANGII on the kidney are quantitatively more important than indirect effects mediated by aldosterone. In older hypertensives, plasma renin activity and aldosterone concentration are often suppressed, perhaps due to loss of functional nephrons and increased sodium chloride delivery to the macula densa of the remaining nephrons.(ABSTRACT TRUNCATED AT 250 WORDS) |
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Authors:
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J E Hall; T G Coleman; A C Guyton |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S.; Review |
Journal Detail:
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Title: Journal of the American Geriatrics Society Volume: 37 ISSN: 0002-8614 ISO Abbreviation: J Am Geriatr Soc Publication Date: 1989 Aug |
Date Detail:
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Created Date: 1989-09-06 Completed Date: 1989-09-06 Revised Date: 2008-03-10 |
Medline Journal Info:
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Nlm Unique ID: 7503062 Medline TA: J Am Geriatr Soc Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 801-13 Citation Subset: IM |
Affiliation:
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Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson 39216. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Aging
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physiology* Aldosterone / physiology Angiotensin II / physiology Blood Pressure Humans Hypertension / physiopathology* Natriuresis Renin-Angiotensin System* Water-Electrolyte Imbalance / physiopathology |
| Grant Support | |
ID/Acronym/Agency:
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HL 11678/HL/NHLBI NIH HHS; HL 23502/HL/NHLBI NIH HHS; HL 39399/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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11128-99-7/Angiotensin II; 52-39-1/Aldosterone |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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