Angiotensin II inhibition with captopril on plasma ADH, PG synthesis, and renal function in humans

1986 ◽  
Vol 250 (6) ◽  
pp. F986-F990 ◽  
Author(s):  
M. Usberti ◽  
G. Di Minno ◽  
B. Ungaro ◽  
B. Cianciaruso ◽  
S. Federico ◽  
...  

Using captopril (C), an angiotensin (ANG) I converting-enzyme inhibitor, to increase endogenous prostaglandins (PGs) and to decrease endogenous ANG II synthesis, we studied the relationship between endogenous ANG II, PG, and antidiuretic hormone (ADH) release in seven normal volunteers before (control study) and after inhibition of PG synthesis by a single dose of aspirin (ASA study). In the control study, following the administration of 100 mg of C, there was a significant increase of plasma PGE2, plasma-renin activity (PRA), and urinary PGE2 and 6-keto-PGF1 alpha and a decrease of plasma ADH. Glomerular filtration rate (GFR) and renal plasma flow (RPF) were unaffected by C; urine output, fractional sodium excretion (FENa), and osmolal clearance (Cosmol) increased; and urinary osmolality (Uosmol) decreased significantly after C. In the ASA study PG were undetectable in plasma and significantly reduced in urine 1 h after aspirin and did not increase when C was added. Plasma ADH decreased and PRA increased, as in the control study, after C, whereas GFR, RPF, urine output, FENa, Cosmol, and Uosmol were unchanged. These results suggest that the effect of C on ADH release may be mediated, to a large extent, by a fall in endogenous circulating ANG II, since ADH decreased in the presence of both high or undetectable levels of PGE2. The results also suggest that the increase in PGE2 induced by C may precipitate the diuretic and natriuretic effects of acute C administration.

1985 ◽  
Vol 248 (2) ◽  
pp. F254-F259 ◽  
Author(s):  
M. Usberti ◽  
S. Federico ◽  
G. Di Minno ◽  
B. Ungaro ◽  
G. Ardillo ◽  
...  

To verify whether angiotensin II (ANG II) stimulates ADH release in humans and to evaluate whether endogenous prostaglandins influence the resulting renal effect of ADH, nonpressor and low pressor doses of ANG II were infused in nine normal volunteers under normal conditions (control study) and after prostaglandin synthesis inhibition with aspirin (ASA study). During ANG II infusion plasma ADH increased in both conditions. Plasma PGE2, urinary PGE2, and urinary 6-keto-PGF1 alpha increased only in the control study, whereas they were undetectable in the plasma and significantly reduced in the urine in the ASA study. ANG II caused a significant fall of glomerular filtration rate, renal plasma flow (with an increase in filtration fraction), fractional sodium excretion, and urine output in both studies. Despite the reduced urine output, urine osmolality decreased significantly in the control study, whereas it increased after aspirin administration. These results suggest that intravenous ANG II stimulates ADH release in humans but that the renal effects of the resulting increase in plasma ADH are different depending on the presence or absence of endogenous prostaglandins.


1982 ◽  
Vol 243 (3) ◽  
pp. F260-F264 ◽  
Author(s):  
P. R. Kastner ◽  
J. E. Hall ◽  
A. C. Guyton

Studies were performed to quantitate the effects of progressive increases in renal venous pressure (RVP) on renin secretion (RS) and renal hemodynamics. RVP was raised in 10 mmHg increments to 50 mmHg. Renin secretion rate increased modestly as RVP was increased to 30 mmHg and then increased sharply after RVP exceeded 30 mmHg. Glomerular filtration rate (GFR), renal blood flow (RBF), and filtration fraction (FF) did not change significantly when RVP was elevated to 50 mmHg. GFR and RBF were also measured after the renin-angiotension system (RAS) was blocked with the angiotensin converting enzyme inhibitor (CEI) SQ 14225. After a 60-min CEI infusion, RBF was elevated (32%), GFR was unchanged, FF was decreased, and total renal resistance (TRR) was decreased. As RVP was increased to 50 mmHg, GFR and FF decreased to 36.3 and 40.0% of control, respectively, RBF returned to a value not significantly different from control, and TRR decreased to 44.8% of control. The data indicate that the RAS plays an important role in preventing reductions in GFR during increased RVP because blockade of angiotensin II (ANG II) formation by the CEI results in marked decreases in GFR at high RVPs. The decreases in GFR after ANG II blockade and RVP elevation were not due to lack of renal vasodilation, since TRR was maintained below while RBF was maintained either above or at the pre-CEI levels.


1985 ◽  
Vol 248 (3) ◽  
pp. F340-F346 ◽  
Author(s):  
J. E. Hall ◽  
J. P. Granger ◽  
R. L. Hester

This study examined interactions between adenosine (Ado) and angiotensin II (ANG II) in controlling renal blood flow (RBF) and glomerular filtration rate (GFR). In six normal dogs, intrarenal Ado infusion (1.0 mumol/min) transiently decreased RBF, but during sustained Ado infusion RBF increased to 122 +/- 7% of control, although GFR remained at 75 +/- 6% of control. Blockade of ANG II formation with the converting enzyme inhibitor SQ 14225 (n = 6) almost abolished the transient decrease in RBF but did not prevent the sustained fall in GFR caused by Ado. When circulating ANG II was held constant by intravenous infusion of SQ 14225 and 20 ng . kg-1 . min-1 of ANG II (n = 6), Ado transiently decreased RBF but the return of RBF was much slower than in normal dogs and RBF did not increase above control. Maintenance of constant circulating ANG II did not prevent Ado-mediated decreases in GFR. These observations suggest that Ado-mediated reductions in GFR do not depend entirely on ANG II and may be due to dilation of efferent arterioles by Ado. However, the transient renal vasoconstriction caused by Ado depends on ANG II, and data from this study suggest that part of the waning constrictor response to Ado is due to suppression of renin secretion and endogenous ANG II formation. In circumstances where high ANG II levels are maintained (i.e., ischemic renal failure), Ado may be capable of causing sustained renal vasoconstriction.


1985 ◽  
Vol 248 (5) ◽  
pp. R541-R548
Author(s):  
B. S. Huang ◽  
R. L. Malvin ◽  
R. J. Grekin

The effects of intracerebroventricular (IVT) infusion of angiotensin II (ANG II), the converting enzyme inhibitor SQ 20881, and dopamine were studied in 15 conscious Na-depleted sheep. IVT ANG II (25 ng/min) significantly increased plasma aldosterone (163 +/- 24%) and vasopressin (ADH) (533 +/- 100%). Plasma renin activity (PRA) was decreased to 64 +/- 10% of basal. IVT SQ (1 microgram/min) decreased aldosterone to 70 +/- 10% and ADH to 55 +/- 9% of basal. PRA increased to 124 +/- 10%. There were no significant changes in plasma Na, K, or cortisol levels nor in mean arterial or intracranial pressure after either infusion. Increasing the dose of SQ to 10 micrograms/min resulted in an increased magnitude of change in the same variables. IVT SQ (1 microgram/min) significantly decreased aldosterone level in five nephrectomized sheep. The responses to IVT dopamine (20 micrograms/min) were qualitatively similar to those elicited by IVT SQ. These data support the existence of an endogenous brain renin-angiotensin system (RAS) independent of the renal RAS. ANG II acts centrally to regulate plasma ADH, aldosterone, and PRA levels. The similarity of the responses to SQ and dopamine suggests that a dopaminergic pathway may be involved in these responses.


1988 ◽  
Vol 255 (3) ◽  
pp. F545-F551
Author(s):  
H. M. Siragy ◽  
N. E. Lamb ◽  
C. E. Rose ◽  
M. J. Peach ◽  
R. M. Carey

The mechanism by which atrial natriuretic peptide (ANP) increases renal water and solute excretion is not fully understood. We studied the renal effects of ANP and angiotensin II (ANG II) separately and together in uninephrectomized conscious dogs (n = 7) in sodium metabolic balance (80 meq/day). Exogenous ANG II and ANP were without measurable systemic effects as demonstrated by absence of changes in blood pressure, plasma aldosterone concentration, and plasma renin activity. The quantity of ANG II that had significant renal effects that were without measurable systemic effects was 0.2 pmol.kg-1.min-1. Three infusion rates of ANP had significant renal effects (1, 10, and 20 pmol.kg-1.min-1). These quantities of ANP caused significant diuresis, natriuresis, kaliuresis, and increased glomerular filtration rate without significant changes in renal plasma flow. ANG II alone caused significant antidiuresis, antinatriuresis, and decreased glomerular filtration rate and renal plasma flow. When ANG II and ANP were given together, no change in urinary flow rate, urinary sodium or potassium excretion, or renal plasma flow was observed, whereas glomerular filtration rate increased. Filtration fraction increased significantly with ANG II and ANP separately and together. Intrarenal ANP prevents the ANG II-induced decrement in urinary sodium excretion and urine flow rate. ANP may play an important role in escape from the sodium-retaining action of intrarenal ANG II.


2020 ◽  
Vol 106 (1) ◽  
pp. e11-e19
Author(s):  
Ali Asmar ◽  
Per K Cramon ◽  
Meena Asmar ◽  
Lene Simonsen ◽  
Charlotte M Sorensen ◽  
...  

Abstract Purpose The natriuretic effect of glucagon-like peptide-1 (GLP-1) in humans is independent of changes in renal plasma flow (RPF) and glomerular filtration rate (GFR) but may involve suppression of angiotensin II (ANG II) and a significant (~45%) renal extraction of GLP-1. The current study was designed to investigate the consequences for the renal extraction and the natriuretic effect of blocking GLP-1 receptors with the specific GLP-1 receptor antagonist, Exendin 9–39 (Ex 9–39). Methods Under fixed sodium intake for 4 days before each study day, 6 healthy male participants were recruited from our recent study where GLP-1 or vehicle was infused (1). In the present new experiments, participants were examined during a 3-hour infusion of GLP-1 (1.5 pmol/kg/min) together with a 3.5-hour infusion of Ex 9–39 (900 pmol/kg/min). Timed urine collections were conducted throughout the experiments. Renal extraction of GLP-1 as well as RPF and GFR were measured via Fick’s principle after catheterization of a renal vein. Arterial plasma renin, ANG II, and aldosterone concentrations were measured. Results Co-infusion of Ex 9–39 significantly reduced renal extraction of GLP-1 to ~25% compared with GLP-1 infusion alone (~45%). Urinary sodium excretions remained at baseline levels during co-infusion of Ex 9–39 as well as vehicle. By contrast, GLP-1 infusion alone resulted in a 2-fold increase in natriuresis. Ex 9–39 abolished the GLP-1-induced decrease in arterial ANG II concentrations. RPF and GFR remained unchanged during all experiments. Conclusions Renal extraction of GLP-1 and its effect on natriuresis are both dependent on GLP-1 receptor activation in healthy humans.


1985 ◽  
Vol 69 (2) ◽  
pp. 207-214 ◽  
Author(s):  
D. P. Worth ◽  
J. N. Harvey ◽  
J. Brown ◽  
M. R. Lee

1. γ-l-Glutamyl-l-dopa was given by intravenous infusion to eight normal subjects at doses of 12.5 and 100 μg min−1 kg−1. 2. Both doses of the dipeptide resulted in an increase in mean urinary sodium excretion. 3. Mean effective renal plasma flow rose at both doses, but mean glomerular filtration rate increased only at the lower dose. 4. There was a fall in mean plasma renin activity after the infusion of both 12.5 and 100 μg min−1kg−1. 5. Mean urine free dopamine excretion increased by 280- and 2500-fold at infusion rates of 12.5 and 100 μg min−1 kg−1 respectively. 6. Mean plasma free dopamine rose at both doses but the increase at 12.5 μg min−1 kg−1 was not to a level previously associated with systemic effects of the catecholamine. 7. On administration of the dipeptide at 12.5 μg min−1 kg−1 there were no changes in blood pressure or heart rate, but at the higher dose there was a fall in diastolic blood pressure. 8. At a dose of 12.5 μg min−1 kg−1 in man, there is kidney specific conversion of gludopa to dopamine.


2003 ◽  
Vol 285 (5) ◽  
pp. R981-R991 ◽  
Author(s):  
Ronni R. Plovsing ◽  
Christian Wamberg ◽  
Niels C. F. Sandgaard ◽  
Jane A. Simonsen ◽  
Niels-Henrik Holstein-Rathlou ◽  
...  

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.


2010 ◽  
Vol 299 (5) ◽  
pp. F954-F962 ◽  
Author(s):  
Torrance Green ◽  
Jorge Rodriguez ◽  
L. Gabriel Navar

Nonsteroidal anti-inflammatory drug usage has long revealed renoprotective prostaglandin actions on the renal microvasculature during increased pressor hormone influence, but whether increased cyclooxygenase (COX)-2 expression supports prostaglandin vasodilatory influence by interfering with the actions of ANG II remains unresolved. Therefore, we tested the hypothesis that COX-2 inhibition causes hemodynamic and excretory effects that are increased in proportion to ANG II activity. In anesthetized Sprague-Dawley rats having augmented cortical COX-2 expression but different ANG II activity, we conducted renal clearance experiments during acute inhibition of COX-2 with nimesulide (NMSLD) and inhibition of COX-1 with SC-560. In one series of experiments, acute captopril [acute angiotensin-converting enzyme (ACE) inhibitor (aACEi)] was administered alone ( n = 13) or in combination with chronic captopril [chronic ACEi (cACEi)] pretreatment ( n = 19). In another series of experiments, rats were fed a normal-sodium [0.4% (NS), n = 12] or a low-sodium [0.03% (LS), n = 18] diet. NMSLD did not alter mean arterial blood pressure in any group but, in the LS and cACEi groups, decreased renal plasma flow (from 3.99 ± 0.33 to 2.85 ± 0.26 and from 4.30 ± 0.19 to 3.22 ± 0.21 ml·min−1·g−1), cortical blood flow (−12 ± 8% and −13 ± 4%), and glomerular filtration rate (from 0.88 ± 0.04 to 0.65 ± 0.05 and from 0.95 ± 0.07 to 0.70 ± 0.05 ml·min−1·g−1). In contrast, medullary blood flow (MBF) was significantly decreased by COX-2 inhibition in NS (−24 ± 5%), LS (−27 ± 8%), aACEi (−16 ± 3.8%), and cACEi (−24 ± 4.2%) groups. Absolute and fractional sodium excretion rates were unchanged by NMSLD, except in the LS group (0.75 ± 0.05 μeq/min and 0.43 ± 0.15% and 0.51 ± 0.06 μeq/min and 0.26 ± 0.10%). SC-560 did not augment the effects of NMSLD. These results demonstrate an augmented COX-2-mediated vasodilation that is not contingent on ANG II, in contrast to COX-2-mediated augmented sodium excretion, where ANG II activity is requisite. Furthermore, the COX-2 effects on MBF are not contingent on ANG II or changes in cortical microvascular responses. These results reflect COX-2 continual regulation of MBF and adaptive opposition to ANG II prohypertensinogenic effects on renal plasma flow, cortical blood flow, glomerular filtration rate, and absolute and fractional sodium excretion.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Xu Xiao ◽  
Hong-jun Du ◽  
Wei-jian Hu ◽  
Peter X. Shaw

Objective. To observe the relationship between changes in renin-angiotensin-aldosterone system (RAAS) activity and blood plasma glucose after administration of hydrochlorothiazide (HCTZ) for one year in patients with hypertension.Methods. 108 hypertensive patients were given 12.5 mg HCTZ per day for one year. RAAS activity, plasma glucose levels, and other biochemical parameters, as well as plasma oxidized low density lipoprotein (oxLDL) levels, were measured and analyzed at baseline, six weeks, and one year after treatment.Results. After one year of treatment, the reduction in plasma glucose observed between the elevated plasma renin activity (PRA) group (-0.26±0.26 mmol/L) and the nonelevated PRA group (-1.36±0.23 mmol/L) was statistically significant (P<0.05). The decrease of plasma glucose in the elevated Ang II group (-0.17±0.18 mmol/L) compared to the nonelevated Ang II group (-1.07±0.21 mmol/L) was statistically significant (P<0.05). The proportion of patients with elevated plasma glucose in the elevated Ang II group (40.5%) was significantly higher than those in the nonelevated Ang II group (16.3%) (P<0.05). The relative oxLDL level was not affected by the treatment.Conclusions. Changes in RAAS activity were correlated with changes in plasma glucose levels after one year of HCTZ therapy.


Sign in / Sign up

Export Citation Format

Share Document