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Plasma Renin (plasma + renin)

Distribution by Scientific Domains

Life Sciences	85%

Terms modified by Plasma Renin

plasma renin activity

Selected Abstracts

Blood volume, blood pressure and total body sodium: internal signalling and output control

ACTA PHYSIOLOGICA, Issue 1 2009
P. Bie
Abstract Total body sodium and arterial blood pressure (ABP) are mutually dependent variables regulated by complex control systems. This review addresses the role of ABP in the normal control of sodium excretion (NaEx), and the physiological control of renin secretion. NaEx is a pivotal determinant of ABP, and under experimental conditions, ABP is a powerful, independent controller of NaEx. Blood volume is a function of dietary salt intake; however, ABP is not, at least not in steady states. A transient increase in ABP after a step-up in sodium intake could provide a causal relationship between ABP and the regulation of NaEx via a hypothetical integrative control system. However, recent data show that subtle sodium loading (simulating salty meals) causes robust natriuresis without changes in ABP. Changes in ABP are not necessary for natriuresis. Normal sodium excretion is not regulated by pressure. Plasma renin is log-linearly related to salt intake, and normally, decreases in renin secretion are a precondition of natriuresis after increases in total body sodium. Renin secretion is controlled by renal ABP, renal nerve activity and the tubular chloride concentrations at the macula densa (MD). Renal nerve activity is related to blood volume, also at constant ABP, and elevates renin secretion by means of ,1 -adrenoceptors. Recent results indicate that renal denervation reduces ABP and renin activity, and that sodium loading may decrease renin without changes in ABP, glomerular filtration rate or ,1 -mediated nerve activity. The latter indicates an essential role of the MD mechanism and/or a fourth mediator of the physiological control of renin secretion. [source]

Plasma renin in mice with one or two renin genes

ACTA PHYSIOLOGICA, Issue 4 2004
P. B. Hansen
Abstract Aim:, In the present study we have investigated whether the presence of a second renin gene exerts an overriding influence on plasma renin such that mice with two renin genes have consistently higher renin levels than mice with only one renin gene. Methods:, Plasma renin was determined as the rate of angiotensin I generation using a radioimmunoassay (RIA) kit with (plasma renin concentration, PRC) or without (plasma renin activity, PRA) the addition of purified rat angiotensinogen as substrate. Results:, In male 129SvJ, DBA/2 and Swiss Webster mice, strains possessing both Ren-1 and Ren-2, PRC (ng Ang I mL,1 h,1) averaged 178 ± 36, 563 ± 57 and 550 ± 43 while PRA was 2.9 ± 0.5, 3.6 ± 0.8 and 7.8 ± 1.2. In male C57BL/6, C3H and BALB/c mice that express only Ren-1, PRC averaged 426 ± 133, 917 ± 105 and 315 ± 72, and PRA was 3.4 ± 1.0, 6.9 ± 1.7 and 4.5 ± 1.2. In the two renin gene A1AR,/, mice compared with the one renin gene A1AR+/+, PRC averaged 538 ± 321 and 415 ± 159 while PRA averaged 3.2 ± 1.1 and 4.4 ± 1.4 ng Ang I mL,1 h,1. Aldosterone levels showed no significant differences between one renin (C57BL/6, C3H and BALB/c) and two renin (129SvJ, DBA/2 and Swiss Webster) gene mice. Furthermore, by quantitative real-time polymerase chain reaction (RT-PCR) we found no correlation between the number of renin genes and whole kidney renin mRNA levels from one and two renin gene mice. Conclusion:, Our data show that baseline plasma renin is not systematically higher in mice with two renin genes than in one renin gene mice. Thus, the presence of a second renin gene does not seem to be a major determinant of differences in PRC between different mouse strains. [source]

Salt-Sensitive Hypertension Resulting From Nitric Oxide Synthase Inhibition is Associated with Loss of Regulation of Angiotensin II in the Rat

EXPERIMENTAL PHYSIOLOGY, Issue 1 2002
G. Hodge
In the Dahl salt-sensitive hypertensive rat, a diet containing L-arginine, the natural substrate for nitric oxide synthase, abrogates the hypertension. We postulated that nitric oxide synthase inhibition might induce a salt-sensitive form of hypertension and that this salt sensitivity might be linked to a loss of the regulatory effect of sodium ingestion on angiotensin II (Ang II) and angiotensinogen. Male Wistar-Kyoto rats were randomised to a diet containing 0.008%, 2.2% or 4.4% sodium chloride and to treatment with the NO synthase inhibitor L-NAME (10 mg kg,1 day,1) in the drinking water, or drinking water alone (Controls) for 4 weeks. Blood pressure was measured by tail cuff plethysmography twice weekly. After 4 weeks, the rats were anaesthetised and truncal blood collected for determination of angiotensinogen, renin, angiotensin I (Ang I), Ang II and aldosterone concentrations as well as angiotensin-converting enzyme (ACE) activity. Systolic blood pressure increased with increasing dietary sodium intake in the L-NAME-treated rats (P < 0.05). Plasma renin and aldosterone concentrations decreased with increasing dietary sodium intake in both Control and L-NAME-treated rats. Ang I and ACE activity were unchanged by increasing dietary sodium intake. In contrast, the plasma concentration of Ang II and angiotensinogen increased with increasing dietary sodium (P < 0.05 and P < 0.005, respectively). Treatment with the Ang II receptor blocker, losartan, reversed the blood pressure increase. We conclude that treatment with L-NAME induces an increase in blood pressure that is at least in part salt sensitive. Further, the salt-sensitive component appears to be Ang II-dependent, as it was associated with increasing plasma Ang II levels and could be reversed by treatment with an Ang II receptor antagonist. [source]

Plasma renin and the antihypertensive effect of the orally active renin inhibitor aliskiren in clinical hypertension

INTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 9 2007
J. Nussberger
Summary Background:, Aliskiren is the first in a new class of orally effective renin inhibitors for the treatment of hypertension. Methods:, In 569 patients with mild-to-moderate hypertension, blood pressure (BP), plasma renin activity (PRA) and plasma renin concentration (PRC) were measured before and after 8 weeks of double-blind treatment with once-daily oral doses of aliskiren (150, 300 or 600 mg), irbesartan 150 mg or placebo. Results:, Aliskiren 150, 300 and 600 mg and irbesartan 150 mg significantly reduced mean cuff sitting systolic BP (SBP) from baseline (p < 0.001 vs. placebo). Aliskiren 150, 300 and 600 mg significantly reduced geometric mean PRA by 69%, 71% and 75% from baseline respectively (p < 0.05 vs. placebo). Irbesartan 150 mg significantly increased PRA by 109% (p < 0.05 vs. placebo). Aliskiren dose-dependently increased PRC from baseline by 157%, 246% and 497%, at 150, 300 and 600 mg respectively, compared with a 9% decrease with placebo (p < 0.05). PRC increased significantly more with aliskiren 300 and 600 mg compared with irbesartan 150 mg (105%; p < 0.05). Regression analysis showed no significant correlations between baseline PRA and changes in SBP in any of the treatment groups, but interestingly, the slopes of the regression lines between changes in SBP and log-transformed baseline PRA were +2.0 for placebo and ,1.5, ,1.8 and ,2.3 for aliskiren 150, 300 and 600 mg respectively. The slope for irbesartan 150 mg (,1.4) was similar to that for aliskiren 150 mg. Conclusions:, Aliskiren reduces SBP and PRA and increases PRC dose-dependently. In contrast, irbesartan reduces SBP but increases both PRC and PRA. As PRA is a measurement of angiotensin I-generating capacity, PRA can be used for measuring the ability of an antihypertensive agent to prevent the generation or action of Ang II, either directly (renin inhibitors, beta-blockers, central ,2 -agonists) or indirectly (AT1 -receptor blockers, ACE inhibitors). [source]