Activity and responsiveness of the renin-angiotensin system in the aging rat
Division of Nephrology and Hypertension, Oregon Health Sciences University, and Portland Veterans Affairs Medical Center, Portland, Oregon 97201 The systemic renin-angiotensin system (RAS) is suppressed in normal aging, but the activity of the tissue RAS is not well defined. We examined the systemic...
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Published in | American journal of physiology. Regulatory, integrative and comparative physiology Vol. 279; no. 5; pp. 1787 - R1794 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
United States
01.11.2000
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Subjects | |
Online Access | Get full text |
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Summary: | Division of Nephrology and Hypertension, Oregon Health Sciences
University, and Portland Veterans Affairs Medical Center, Portland,
Oregon 97201
The systemic renin-angiotensin system (RAS) is
suppressed in normal aging, but the activity of the tissue RAS is not
well defined. We examined the systemic and intrarenal RAS status of aging normal rats and responses to suppression and stimulation of the
production of endogenous ANG II. Studies were performed in
young (3 mo) and early aging (15 mo) male Sprague-Dawley rats. Angiotensin-converting enzyme inhibitors modestly decreased mean arterial pressure (MAP) in young (3 mo) and early aging (15 mo) rats
and limited proteinuria in the older rats. There were no significant
age-related effects on renal function or on endogenous RAS activity.
Intravenous infusion of the precursor ANG I led to comparable increases
in MAP in younger and older rats. In contrast, the renal effects
(reduction in glomerular filtration and plasma flow rates) were
exaggerated in the older animals. Intrarenal arterial ANG I did not
affect MAP in any group. In young rats, there were no significant
hemodynamic effects in either the ipsilateral (infused) or the
contralateral (noninfused) kidney. In the older rats, both kidneys had
a significant fall in renal renal plasma flow rate (RPF) with left
renal arterial infusion of ANG I. Accordingly, these studies early in
the course of aging found only subtle changes in the activity,
responsiveness, and metabolism of the RAS. Thus early aging is
associated with a modest but important increase in sensitivity to RAS stimulation.
glomerular filtration rate; proteinuria; kidney |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0363-6119 1522-1490 |
DOI: | 10.1152/ajpregu.2000.279.5.R1787 |