TY - JOUR
T1 - Activity and responsiveness of the renin-angiotensin system in the aging rat
AU - Thompson, Michele M.
AU - Oyama, Terry T.
AU - Kelly, Francis J.
AU - Kennefick, Thomas M.
AU - Anderson, Sharon
PY - 2000
Y1 - 2000
N2 - 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.
AB - 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.
KW - Glomerular filtration rate
KW - Kidney
KW - Proteinuria
UR - http://www.scopus.com/inward/record.url?scp=0033668316&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033668316&partnerID=8YFLogxK
U2 - 10.1152/ajpregu.2000.279.5.r1787
DO - 10.1152/ajpregu.2000.279.5.r1787
M3 - Article
C2 - 11049862
AN - SCOPUS:0033668316
SN - 0363-6119
VL - 279
SP - R1787-R1794
JO - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
JF - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
IS - 5 48-5
ER -