Inhibition of the Renin-Angiotensin-Aldosterone System by l-Dopa with and without Inhibition of Extracerebral Dopa Decarboxylase in Man

1981 ◽  
Vol 61 (2) ◽  
pp. 187-190 ◽  
Author(s):  
C. Barbieri ◽  
R. Caldara ◽  
C. Ferrari ◽  
Rosa Maria Crossignani ◽  
M. Recchia
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Plasma Renin ◽  
Normal Subjects ◽  
Plasma Aldosterone ◽  
Renin Angiotensin Aldosterone System ◽  
Plasma Aldosterone Concentration ◽  
Renin Angiotensin ◽  
Drugs Analysis ◽  
Catecholamine Levels

1. The present study was undertaken to investigate the possibility that central nervous system mono-aminergic pathways may play a role in the control of the renin-angiotensin-aldosterone system in man. 2. Eight normal subjects received in a randomized order placebo, l-dopa (500 mg, orally) and l-dopa (100 mg, orally) plus carbidopa (35 mg, orally) after pretreatment with carbidopa (50 mg every 6 h for four doses). 3. l-Dopa administration elicited a significant fall in plasma renin activity (PRA) (P < 0.01 at 120, 150 and 180 min) and in plasma aldosterone levels (P < 0.05 at 90, 120, 150 and 180 min); L-dopa plus carbidopa induced a decrease in PRA (P < 0.05 at 120 and 150 min, P < 0.01 at 180 min) and in plasma aldosterone concentration (P < 0.05 at 30 and 60 min, P < 0.01 at 90 and 120 min), in comparison with placebo administration; between-drugs analysis revealed no difference in the decreases in PRA and plasma aldosterone levels induced by the two regimens. 4. Since l-dopa, as well as l-dopa plus carbidopa, has been shown to augment catecholamine levels in the brain of various animal species, the present data suggest that in man PRA and plasma aldosterone concentration might be inhibited by increased central nervous system catecholamine levels.

Factors affecting Potassium Balance During Frusemide Administration

1984 ◽  
Vol 67 (2) ◽  
pp. 195-203 ◽  
Author(s):  
Christopher S. Wilcox ◽  
William E. Mitch ◽  
Ralph A. Kelly ◽  
Paul A. Friedman ◽  
Paul F. Souney ◽  
...  
Keyword(s):  
Salt Intake ◽  
Normal Subjects ◽  
Plasma Aldosterone ◽  
High Salt ◽  
Renin Angiotensin Aldosterone System ◽  
Plasma Aldosterone Concentration ◽  
Water Load ◽  
Renin Angiotensin ◽  
High Salt Intake ◽  
Low Salt

1. We investigated the effects of Na+ intake, the renin-angiotensin-aldosterone system and antidiuretic hormone (ADH) on K+ balance during 3 days of frusemide administration to six normal subjects. Subjects received 40 mg of frusemide for 3 days during three different protocols: Na+ intake 270 mmol/day (high salt); Na+ intake 20 mmol/day to stimulate the renin-angiotensin-aldosterone system (low salt); Na+ intake 270 mmol/day plus captopril (25 mg/6 h) to prevent activation of the renin-angiotensin-aldosterone system. In a fourth protocol, a water load was given during high salt intake to prevent ADH release and then frusemide was given. 2. During high salt intake, frusemide increased K+ excretion (UKV) over 3 h, but the loss was counterbalanced by subsequent renal K+ retention so that daily K+ balance was neutral. 3. During low salt intake, the magnitude of the acute kaliuresis following the first dose of frusemide and the slope of the linear relationship between UKV and the log of frusemide excretion were increased compared with that found during the high salt intake. In addition, low salt intake abolished the compensatory renal retention of K+ after frusemide and cumulative K+ balance over 3 days of diuretic administration was uniformly negative (−86 ± 7 mmol/3 days; P < 0.001). 4. Captopril abolished the rise in plasma aldosterone concentration induced by frusemide. The acute kaliuresis after frusemide was unchanged compared with that observed during high salt intake. The compensatory reduction in UKV occurring after the diuretic was slightly potentiated. In fact, captopril given without the diuretic induced a small positive K+ balance. 5. When a water load was given concurrently with frusemide, the acute kaliuresis was >30% lower compared with that seen with frusemide alone, even though the natriuretic response was unchanged. 6. We conclude that: (a) K+ balance is maintained when frusemide is given during liberal Na+ intake because acute K+ losses are offset by subsequent renal K+ retention; (b) this compensatory K+ retention can be inhibited by aldosterone release which could account for the negative K+ balance seen during salt restriction; (c) the short-term kaliuretic response to frusemide is augmented by release of both ADH and aldosterone whereas changes in K+ balance over 3 days of frusemide are dependent on plasma aldosterone concentration.

scholarly journals RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM IN PATIENTS WITH ABDOMINAL OBESITY AND ARTERIAL HYPERTENSION

2013 ◽  
Vol 19 (5) ◽  
pp. 389-396 ◽  
Author(s):  
E. A. Bazhenova ◽  
O. D. Belyaeva ◽  
A. V. Berezina ◽  
T. L. Karonova ◽  
D. A. Kolodina ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Plasma Renin ◽  
Plasma Aldosterone ◽  
Obese Patients ◽  
Renin Angiotensin Aldosterone System ◽  
Plasma Aldosterone Concentration ◽  
Renin Angiotensin ◽  
Primary Disorder ◽  
Per Se ◽  
Design And Methods

Objective. The activity of renin-angiotensin-aldosterone system (RAAS) is increased in patients with ab-dominal obesity (AO). However, till present time it is unclear whether RAAS activation or hypertension (HTN) found in 50 % patients is the primary disorder.Design and methods. We have studied plasma renin activity (PRA), plasma aldosterone concentration (PAC), their ratio PAC/PRA in patients with AO and related HTN and in subjects without AO.Results. PRA was higher in patients with AO versus people without obesity (2,5 ± 0,2 and 1,7 ± 0,7 ng/ml/hr, p = 0,013), there was a tendency to the reduction of the ratio PAC/PRA in obese patients (14,6 ± 0,9 and 19,7 ± 3,3, p = 0,08). In the subgroup of patients with AO and HTN the PRA was higher, and the ratio PAC/PRA was lower than in obese patients without HTN (PRA: 3,3 ± 0,4 and 1,7±0,2 ng/ml/hr, p = 0,005; PAC/PRA: 11,4 ± 1,1 and 17,4 ± 1,4, p < 0,0001). PRA and systolic blood pressure positively correlated. In patients with morbid obesity (3 degree according to the WHO classiication) obesity may play a signiicant role in the increase of RAAS activity, especially in the absence of concomitant HTN. The ratio PAC/PRA in over weight patients with AO was higher than in patients with AO and body mass index ? 30,0 kg/m (17,2 ± 1,7 and 12,5 ± 1,0 kg/m, p = 0,04). PRA was higher only in patients with AO and co-existing hypertension (3,4 ± 0,7 and 1,1 ± 0,2 ng/ml/hr, p = 0,04).Conclusions. RAAS activity is increased in patients with AO, also due to the co-existing HTN. However, in the absence of elevated blood pressure obesity per se may play a signiicant role in RAAS hyperactivity.

Evidence for two independent effects of oestradiol benzoate on the renin-angiotensin-aldosterone system

1982 ◽  
Vol 100 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Helmut Kaulhausen ◽  
Cornelia Weyand
Keyword(s):  
Time Course ◽  
Plasma Renin ◽  
Plasma Aldosterone ◽  
Renin Activity ◽  
Renin Substrate ◽  
Renin Angiotensin Aldosterone System ◽  
Plasma Aldosterone Concentration ◽  
Renin Angiotensin ◽  
Oestradiol Benzoate ◽  
Independent Effects

Abstract. Plasma renin concentrations (PRC), plasma renin substrate concentration (PRS), plasma aldosterone and cortisol concentrations as well as plama renin activity (PRA) were measured in ovariectomized subjects after im administration of 10 mg oestradiol benzoate (EB). The esterified oestrogen exerts two independent effects on the renin-angiotensin-aldosterone system. 1) 48 h after EB administration, PRS was significantly increased. Similar results were obtained for total plasma cortisol, reflecting transcortin concentration. In both cases, the increase was quantitatively related to the basal concentrations. These observations are consistent with the well known oestrogen-induced protein synthesis in the liver. 2) The elevation of PRC preceded that of PRS and was already significant 11 h after EB injection. The early rise in plasma renin activity was essentially caused by the increase in PRC, whereas an influence of the activated substrate synthesis was found later, between the 2nd and the 4th day post injection. The time course of plasma aldosterone concentration correlated well with the increased PRA. The results provide evidence that EB has two different effects on the renin-aldosterone axis: an early one by elevating renin release and a delayed one by increasing renin substrate synthesis. Whereas the second mechanism can clearly be localized in the liver, extrarenal as well as direct renal effects of EB may be responsible for the renin stimulation.

Independence of salt intake induced by calcium deprivation from the renin-angiotensin-aldosterone system

1993 ◽  
Vol 264 (3) ◽  
pp. R492-R499 ◽  
Author(s):  
M. G. Tordoff ◽  
D. M. Pilchak ◽  
R. L. Hughes
Keyword(s):  
Salt Intake ◽  
Plasma Renin ◽  
Calcium Deficiency ◽  
Plasma Aldosterone ◽  
Sodium Balance ◽  
Plasma Sodium ◽  
Receptor Blockade ◽  
Renin Angiotensin Aldosterone System ◽  
Angiotensin System ◽  
Renin Angiotensin

We investigated whether the elevated NaCl intake shown by calcium-deprived rats is mediated by the renin-angiotensin-aldosterone system. First, we looked for manifestations of altered renin-angiotensin-aldosterone system activity during the progression of calcium deficiency. There were no differences between control and calcium-deprived rats in plasma aldosterone concentrations, plasma renin activity, plasma sodium concentrations, sodium balance, or blood pressure. Second, we used selective pharmacological antagonists to examine whether disruption of the renin-aldosterone-angiotensin system influenced salt intake. Blockade of aldosterone receptors with spironolactone (25 mg.kg-1 x day-1 sc for 7 days) had no effect on NaCl intake of control or calcium-deprived rats. Angiotensin AT1 receptor blockade with losartan potassium (0.5-10 mg/kg orally) had no effect on NaCl intake of control or calcium-deprived rats but doses > 0.5 mg/kg decreased NaCl intake of adrenalectomized rats. Taken together, these findings indicate that the renin-angiotensin-aldosterone system does not mediate the increased NaCl intake produced by calcium deficiency. The appetite for salt produced by calcium deficiency involves a different physiological substrate from most other models of NaCl intake.

scholarly journals Effect of renal denervation on catecholamines and the renin–angiotensin–aldosterone system

2020 ◽  
Vol 21 (3) ◽  
pp. 147032032094309
Author(s):  
Lida Feyz ◽  
Sjoerd van den Berg ◽  
Robert Zietse ◽  
Isabella Kardys ◽  
Jorie Versmissen ◽  
...  
Keyword(s):  
Plasma Renin ◽  
Drug Regimen ◽  
Plasma Aldosterone ◽  
Renal Sympathetic Denervation ◽  
Renin Angiotensin Aldosterone System ◽  
Renin Angiotensin ◽  
Post Procedure ◽  
Endogenous Catecholamines ◽  
Significant Change ◽  
Renal Sympathetic

Introduction: The effect of renal sympathetic denervation (RDN) on neurohormonal responses is largely unknown. We aimed to assess the effect of RDN on the renin–angiotensin–aldosterone system (RAAS) and endogenous catecholamines. Methods: A total of 60 patients with hypertension underwent RDN and remained on a stable antihypertensive drug regimen. Samples for plasma aldosterone, plasma renin and urine (nor)metanephrine were collected at baseline and at 6 months post procedure. Ambulatory blood pressure (BP) recordings were obtained at baseline and at 6 months post procedure. Results: Mean age was 64±9 years, and 30/60 patients were male. At 6 months, average daytime systolic and diastolic ambulatory BP decreased by 10 and 6 mmHg, respectively ( p<0.001). No significant change was observed in plasma aldosterone (median=248.0 pmol/L (interquartile range (IQR) 113.3–369.5 pmol/L) vs. median=233.0 pmol/L (IQR 110.3–360.8 pmol/L); p=0.66); renin (median=19.5 µIU/mL (IQR 6.8–119.5 µIU/mL) vs. median=14.3 µIU/mL (IQR 7.2–58.0 µIU/mL); p=0.32), urine metanephrine (median=0.46 µmol/L (IQR 0.24–0.77 µmol/L) vs. median=0.46 µmol/L (IQR 0.22–0.88 µmol/L); p=0.75) and normetanephrine (median=1.41 µmol/L (IQR 0.93–2.00 µmol/L vs. median =1.56 (IQR 0.74–2.50 µmol/L); p=0.58) between baseline and 6 months, respectively. No correlation was found between the decrease in mean systolic daytime BP and changes in RAAS hormones or endogenous catecholamines. Conclusion: Despite significant reductions in ambulatory BP, RDN did not result in a significant change in endogenous catecholamines or in RAAS hormones at 6 months.

Renal adaptation and gut hormone release during sodium restriction in ileostomized man

1985 ◽  
Vol 69 (3) ◽  
pp. 299-308 ◽  
Author(s):  
R. J. Unwin ◽  
S. Moss ◽  
W. S. Peart ◽  
Jane Wadsworth
Keyword(s):  
Test Meal ◽  
Plasma Renin ◽  
Normal Subjects ◽  
Significant Rise ◽  
Plasma Aldosterone ◽  
Sodium Restriction ◽  
Gut Peptides ◽  
Plasma Aldosterone Concentration ◽  
Gut Hormone ◽  
Renal Adaptation

1. The renal excretion of water, electrolytes, aldosterone and kallikrein was monitored in 12 ileostomized patients before and during sodium deprivation. Changes in plasma renin activity (PRA), plasma aldosterone and plasma arginine vasopressin (AVP) concentrations were measured, together with aldosterone in ileal fluid. The pattern of gut peptide release in response to a test meal was also examined to assess whether a circulating gut peptide might be involved in the renal adaptation to sodium restriction, and compared with healthy normal subjects who were under no dietary constraint. 2. In each patient renal sodium excretion fell within 8–12 h of sodium deprivation and was associated with a prompt and significant rise in PRA; much later increases in plasma aldosterone concentration and renal aldosterone excretion occurred, and were established by day 2 of sodium restriction. No consistent change in renal kallikrein excretion was found. 3. Ileal sodium loss was little changed by sodium deprivation, but ileal potassium concentration rose steadily and became significantly correlated with PRA, and to a lesser extent with renal aldosterone excretion. 4. Of the gut peptides measured in plasma, only the insulin profile was altered by sodium deprivation, with an increase in the test meal response; insulin has previously been shown to have a significant antinatriuretic action at physiological concentrations. Plasma levels of pancreatic polypeptide and motilin were increased in ileostomized patients when compared with normal subjects, but were unaffected by the change to a low sodium diet. 5. An early increase in urine flow and water diuresis occurred during sodium deprivation, following a cyclical pattern with peaks each evening. There were no corresponding changes in measured plasma AVP concentration or creatinine clearance. This observation remains unexplained.

Dissociation of Renin-Aldosterone and Renal Prostaglandin E during Volume Expansion Induced by Immersion in Normal Man

1980 ◽  
Vol 59 (1) ◽  
pp. 55-62 ◽  
Author(s):  
M. Epstein ◽  
M. D. Lifschitz ◽  
R. Re ◽  
E. Haber
Keyword(s):  
Plasma Renin Activity ◽  
Volume Expansion ◽  
Water Immersion ◽  
Plasma Renin ◽  
Normal Subjects ◽  
Plasma Aldosterone ◽  
Renin Activity ◽  
Prostaglandin E ◽  
Plasma Aldosterone Concentration ◽  
Normal Man

1. The relationship of the renin-angiotensin-aldosterone axis with renal prostaglandin E is complex. Although studies have suggested that these two hormonal systems respond to experimental manipulations in a parallel manner, their interdependence has not been assessed fully during volume expansion. Since studies have demonstrated that in normal man the central hypervolaemia induced by water immersion to the neck produces a prompt and profound suppression of plasma renin activity and plasma aldosterone concentration without concomitant alteration of plasma composition, immersion afforded a unique opportunity to assess simultaneously the effects of central hypervolaemia on plasma renin activity, plasma aldosterone concentration and prostaglandin E excretion. 2. Seven normal subjects were studied twice while in balance on a diet containing 10 mmol of sodium/day, 100 mmol of potassium/day: with indomethacin administration (50 mg given every 6 h for five doses) and without indomethacin. Urinary prostaglandin E excretion was measured hourly and plasma renin activity and plasma aldosterone concentration at 30 min intervals. 3. Immersion was associated with a marked suppression of plasma renin activity (59 ± 7%) and plasma aldosterone concentration (55 ± 3%) with a return to pre-study values during the recovery hour. Concomitantly, urinary prostaglandin E excretion increased from 4.7 to a peak of 10.9 ng/min. Although administration of indomethacin lowered the basal rate of urinary prostaglandin E excretion and plasma renin activity, it did not prevent the subsequent augmentation of urinary prostaglandin E or the suppression of plasma renin activity and plasma aldosterone during the subsequent 4 h of immersion. 4. These results demonstrate a dissociation of renin-aldosterone and prostaglandin E during hypervolaemia and suggest that whereas prostaglandin E may constitute one of the major determinants of renin release clinically and experimentally, these two hormonal systems can be dissociated from each other in response to central volume expansion in man.

Acromegaly and hypertension: role of the renin-angiotensin-aldosterone system

1982 ◽  
Vol 100 (4) ◽  
pp. 581-587 ◽  
Author(s):  
Bengt E. Karlberg ◽  
Anna-Maria Ottosson
Keyword(s):  
Blood Pressure ◽  
High Frequency ◽  
Plasma Renin ◽  
Plasma Aldosterone ◽  
Substantial Part ◽  
Volume Factor ◽  
Renin Angiotensin Aldosterone System ◽  
Renin Angiotensin ◽  
Before And After

Abstract. The incidence of arterial hypertension was evaluated in a partly retrospective study of patients with active acromegaly. Of 37 patients studied, 18 (48%) had hypertension, i.e. a supine blood pressure of > 160/95 mmHg. The type of hypertension was explored further by measuring plasma renin activity and, in some patients plasma aldosterone concentrations before and after stimulation (upright posture or furosemide 80 mg given orally). Urinary 24 h excretion of aldosterone was also determined. About half of the patients with hypertension but also a substantial part of normotensive acromegalics had inappropriately low plasma renin levels both during basal conditions and after stimulation. On the other hand urinary aldosterone excretion was either normal or (in 2 patients) slightly elevated. There was no other evidence of coexistent primary aldosteronism. Our results confirm previous reports of a high frequency of alterations in the renin-angiotensin-aldosterone system in acromegalic patients with growth hormone excess which in some instances may lead to an elevated blood pressure. The biochemical changes have many similarities to low renin essential hypertension. A volume factor may be operating in acromegalic patients with hypertension since in 10 patients treatment with the aldosterone antagonist, spironolactone, with doses between 50–200 mg daily lowered blood pressure to near normal levels. Thus, spironolactone seems to be a worthwhile alternative in the treatment of hypertensive acromegalics.

The Role of Intrarenal Vasoactive Substances in the Pathogenesis of Essential Hypertension

1978 ◽  
Vol 55 (s4) ◽  
pp. 363s-366s ◽  
Author(s):  
K. Abe ◽  
M. Yasujima ◽  
N. Irokawa ◽  
M. Seino ◽  
S. Chiba ◽  
...  
Keyword(s):  
Essential Hypertension ◽  
Urinary Excretion ◽  
Plasma Renin ◽  
Normal Subjects ◽  
Prostaglandin E ◽  
Plasma Aldosterone Concentration ◽  
Renin Angiotensin ◽  
Vasoactive Substances ◽  
Angiotensin Ii Antagonist ◽  
Renal Kallikrein

To investigate the role of renal vasoactive substances in the pathogenesis of essential hypertension, urinary prostaglandin E excretion, urinary kallikrein excretion, plasma renin activity, plasma aldosterone concentration and urinary Na excretion were measured in normal subjects and patients with essential hypertension after stimulation of the renin—angiotensin—aldosterone system by the intravenous injection of frusemide or a low Na diet; after the inhibition of renin—angiotensin—aldosterone by an angiotensin II antagonist and after the inhibition of renal prostaglandin E synthesis by indomethacin. The urinary excretions of prostaglandin E and kallikrein, plasma renin activity and plasma aldosterone concentration increased after frusemide administration. The urinary excretion of kallikrein increased after frusemide or a low Na diet but decreased after the angiotensin II antagonist and indomethacin during Na depletion. Changes in urinary kallikrein excretion paralleled those in the renin—angiotensin—aldosterone system after various stimuli. The urinary excretion of prostaglandin E increased after frusemide. However, a dissociation between the urinary excretions of prostaglandin E and kallikrein was found during the low Na diet: the former decreased and the latter increased. The urinary excretion of prostaglandin E was closely related to urinary Na output after various stimuli. Basal levels of urinary prostaglandin E and kallikrein excretion were lower in essential hypertension than in normal subjects. The release of renal prostaglandin E and kallikrein after frusemide was also suppressed in essential hypertension compared with that in normal subjects. The data indicate that renal kallikrein—kinin and renin—angiotensin—aldosterone may interact in a dynamic fashion to maintain blood pressure, that renal prostaglandin E may be involved in renal Na handling and that the suppression of renal kallikrein—kinin and prostaglandin E in essential hypertension may be an etiological factor in essential hypertension.

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