|
|
||||||||
THIRST AND VOLUME, ELECTROLYTE HOMEOSTASIS
1Department of Physiology and Pharmacology, Institute of Medical Biology, University of Southern Denmark; and 2Department of Nuclear Medicine, Odense University Hospital, DK-5000 Odense; and 3Department of Medical Physiology, The Panum Institute, University of Copenhagen, DK-2200 Copenhagen, Denmark
Submitted 12 May 2003 ; accepted in final form 7 July 2003
Angiotensins different from ANG II exhibit biological activities, possibly mediated via receptors other than ANG II receptors. We studied the effects of 3-h infusions of ANG III, ANG-(1-7), and ANG IV in doses equimolar to physiological amounts of ANG II (3 pmol · kg-1 · min-1), in six men on low-sodium diet (30 mmol/day). The subjects were acutely pretreated with canrenoate and captopril to inhibit aldosterone actions and ANG II synthesis, respectively. ANG II infusion increased plasma angiotensin immunoreactivity to 53 ± 6 pg/ml (+490%), plasma aldosterone to 342 ± 38 pg/ml (+109%), and blood pressure by 27%. Glomerular filtration rate decreased by 16%. Concomitantly, clearance of endogenous lithium fell by 66%, and fractional proximal reabsorption of sodium increased from 77 to 92%; absolute proximal reabsorption rate of sodium remained constant. ANG II decreased sodium excretion by 70%, potassium excretion by 50%, and urine flow by 80%, whereas urine osmolality increased. ANG III also increased plasma aldosterone markedly (+45%), however, without measurable changes in angiotensin immunoreactivity, glomerular filtration rate, or renal excretion rates. During vehicle infusion, plasma renin activity decreased markedly (
700 to
200 mIU/l); only ANG II enhanced this decrease. ANG-(1-7) and ANG IV did not change any of the measured variables persistently. It is concluded that 1) ANG III and ANG IV are cleared much faster from plasma than ANG II, 2) ANG II causes hypofiltration, urinary concentration, and sodium and potassium retention at constant plasma concentrations of vasopressin and atrial natriuretic peptide, and 3) a very small increase in the concentration of ANG III, undetectable by usual techniques, may increase aldosterone secretion substantially.
healthy humans; angiotensin peptides; aldosterone secretion; sodium excretion
This article has been cited by other articles:
![]() |
S. H. Padia, B. A. Kemp, N. L. Howell, M.-C. Fournie-Zaluski, B. P. Roques, and R. M. Carey Conversion of Renal Angiotensin II to Angiotensin III Is Critical for AT2 Receptor-Mediated Natriuresis In Rats Hypertension, February 1, 2008; 51(2): 460 - 465. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. C. Q. Velez, A. M. Bland, J. M. Arthur, J. R. Raymond, and M. G. Janech Characterization of renin-angiotensin system enzyme activities in cultured mouse podocytes Am J Physiol Renal Physiol, July 1, 2007; 293(1): F398 - F407. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. H. Padia, B. A. Kemp, N. L. Howell, H. M. Siragy, M.-C. Fournie-Zaluski, B. P. Roques, and R. M. Carey Intrarenal Aminopeptidase N Inhibition Augments Natriuretic Responses to Angiotensin III in Angiotensin Type 1 Receptor-Blocked Rats Hypertension, March 1, 2007; 49(3): 625 - 630. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. L. Reudelhuber A Place in Our Hearts for the Lowly Angiotensin 1-7 Peptide? Hypertension, May 1, 2006; 47(5): 811 - 815. [Full Text] [PDF] |
||||
![]() |
D. N. Muller and F. C. Luft Direct Renin Inhibition with Aliskiren in Hypertension and Target Organ Damage Clin. J. Am. Soc. Nephrol., March 1, 2006; 1(2): 221 - 228. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. M. Ferrario, A. J. Trask, and J. A. Jessup Advances in biochemical and functional roles of angiotensin-converting enzyme 2 and angiotensin-(1-7) in regulation of cardiovascular function Am J Physiol Heart Circ Physiol, December 1, 2005; 289(6): H2281 - H2290. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. R. Kirchheim Our fragmentary knowledge of the regulatory functions of ANG II "fragments": are we beginning to see the light? Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2003; 285(5): R937 - R938. [Full Text] [PDF] |
||||
![]() |
C. Wamberg, R. R. Plovsing, N. C. F. Sandgaard, and P. Bie Effects of different angiotensins during acute, double blockade of the renin system in conscious dogs Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2003; 285(5): R971 - R980. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |