Role of Prostaglandin in the Antihypertensive Mechanism of Captopril in Low Renin Hypertension

1980 ◽  
Vol 59 (s6) ◽  
pp. 141s-144s ◽  
Author(s):  
Keishi Abe ◽  
Toru Ito ◽  
Makito Sato ◽  
Toshiaki Haruyama ◽  
KO Sato ◽  
...  

1. The role of endogenous prostaglandins in the antihypertensive mechanism of the angiotensin converting enzyme inhibitor, captopril, was investigated. 2. An unequivocal reduction in blood pressure and significant increase in plasma renin activity and urinary prostaglandin E excretion were found after the captopril administration. 3. The changes in blood pressure, plasma renin activity and urinary prostaglandin E excretion induced by captopril were reversed after the inhibition of endogenous prostaglandin synthesis by indomethacin. However, the responses in low renin hypertension were different from those in normal renin hypertension. 4. In low renin hypertensive patients who responded to captopril, the hypotensive effect was abolished after the addition of indomethacin, whereas no marked change in blood pressure was induced by indomethacin in normal renin hypertensive patients. In contrast, plasma renin activity was markedly increased after captopril administration in normal renin hypertension, and no significant change was found in low renin hypertension. 5. Potentiation of the prostaglandin system seems to be a principal factor in the antihypertensive mechanism of captopril in low renin hypertension, and inhibition of the renin-angiotensin system is important in normal renin hypertensives. 6. The increase in renin release after the administration of captopril was inhibited by indomethacin, suggesting that an endogenous prostaglandin system may contribute to the short feedback mechanism of renin release.

1982 ◽  
Vol 63 (2) ◽  
pp. 121-125 ◽  
Author(s):  
S. Swart ◽  
R. F. Bing ◽  
J. D. Swales ◽  
H. Thurston

1. Plasma renin activity, body weight and blood pressure were measured before and after 7 days' treatment with bendrofluazide in ten hypertensive subjects. They were then treated with bendrofluazide alone (5 mg daily) for a minimum of 3 years. The diuretic was then discontinued and the measurements were repeated before and again after 7 days with bendrofluazide. The results were compared with those obtained before chronic treatment with the diuretic. 2. Chronic diuretic treatment was associated with a persistent and progressive rise in plasma renin activity, that fell promptly to pretreatment levels when diuretics were discontinued. This was associated with significant weight gain but no immediate significant rise in blood pressure. 3. When acutely challenged with bendrofluazide the patients showed a greater increase in plasma renin activity on the second occasion than on the first. Three out of five patients with an initially subnormal response had normal responses after chronic diuretic treatment. 4. Chronic diuretic treatment increased the responsiveness of the juxtaglomerular apparatus in some hypertensive patients. 5. Classification of hypertensive patients into renin subgroups may be influenced by previous therapy, even when that therapy has been discontinued for 4 weeks. In particular ‘low renin hypertension’ may be masked by recent use of diuretics, as shown by three of the five patients in this subgroup in the present study.


2021 ◽  
Vol 9 (1) ◽  
pp. 46-53
Author(s):  
V.H. Psarova ◽  
M.M. Kochuieva ◽  
G.I. Kochuiev

The aim of the research: to evaluate the effect of plasma renin activity on the state of hemodynamic and neurohumoral parameters in obese hypertensive patients. Anthropometric, biochemical, automated methods of immune analysis, spectrophotometric, instrumental, statistical methods were used to examine 200 hypertensive patients with class I–II obesity aged 45–55 years. Patients were divided into two groups depending on plasma renin activity: the first group included 21 patients with low-renin hypertension, the second – 179 patients with high-renin hypertension. Patients with HRAH had higher blood pressure BP (DBP, p = 0.004, SBP and mean blood pressure, p<0.001 for both indicators), higher CIMT bifurcation (p = 0.003) and cPWV (p = 0.023), larger size of the left ventricle and its MM (p = 0.039) compared with patients with LRAH. The HRAH was associated with a more pronounced imbalance of the oxidative stress system – antioxidant protection, higher levels of leptin, total cholesterol and LDL cholesterol. In the absence of differences in glycemic levels, patients with HRAH had significantly higher insulin levels and more pronounced IR, as assessed by the HOMA index. Patients with low plasma renin activity had significantly lower serum aldosterone levels with significantly higher ARR levels than patients with high plasma renin activity. Features of cardiovascular remodeling and neurohumoral status depending on the phenotype of hypertension in patients with concomitant obesity have been established.


1984 ◽  
Vol 62 (1) ◽  
pp. 116-123 ◽  
Author(s):  
Ernesto L. Schiffrin ◽  
Jolanta Gutkowska ◽  
Gaétan Thibault ◽  
Jacques Genest

The angiotensin I converting enzyme (ACE) inhibitor enalapril (MK-421), at a dose of 1 mg/kg or more by gavage twice daily, effectively inhibited the pressor response to angiotensin I for more than 12 h and less than 24 h. Plasma renin activity (PRA) did not change after 2 or 4 days of treatment at 1 mg/kg twice daily despite effective ACE inhibition, whereas it rose significantly at 10 mg/kg twice daily. Blood pressure fell significantly and heart rate increased in rats treated with 10 mg/kg of enalapril twice daily, a response which was abolished by concomitant angiotensin II infusion. However, infusion of angiotensin II did not prevent the rise in plasma renin. Enalapril treatment did not change urinary immunorcactive prostaglandin E2 (PGE2) excretion and indomethacin did not modify plasma renin activity of enalapril-treated rats. Propranolol significantly reduced the rise in plasma renin in rats receiving enalapril. None of these findings could be explained by changes in the ratio of active and inactive renin. Water diuresis, without natriuresis and with a decrease in potassium urinary excretion, occurred with the higher dose of enalapril. Enalapril did not potentiate the elevation of PRA in two-kidney one-clip Goldblatt hypertensive rats. In conclusion, enalapril produced renin secretion, which was in part β-adrenergically mediated. The negative short feedback loop of angiotensin II and prostaglandins did not appear to be involved. A vasodilator effect, apparently independent of ACE inhibition, was found in intact conscious sodium-replete rats.


2010 ◽  
Vol 391 (12) ◽  
Author(s):  
M. David Percival ◽  
Sylvie Toulmond ◽  
Nathalie Coulombe ◽  
Wanda Cromlish ◽  
Sylvie Desmarais ◽  
...  

Abstract Renin is the first enzyme in the renin-angiotensin-aldosterone system which is the principal regulator of blood pressure and hydroelectrolyte balance. Previous studies suggest that cathepsin B is the activator of the prorenin zymogen. Here, we show no difference in plasma renin activity, or mean arterial blood pressure between wild-type and cathepsin B knockout mice. To account for potential gene compensation, a potent, selective, reversible cathepsin B inhibitor was developed to determine the role of cathepsin B on prorenin processing in rats. Pharmacological inhibition of cathepsin B in spontaneously hypertensive and double transgenic rats did not result in a reduction in renal mature renin protein levels or plasma renin activity. We conclude that cathepsin B does not play a significant role in this process in rodents.


1983 ◽  
Vol 244 (1) ◽  
pp. R74-R77 ◽  
Author(s):  
J. Schwartz ◽  
I. A. Reid

The role of vasopressin in the regulation of blood pressure during water deprivation was assessed in conscious dogs with two antagonists of the vasoconstrictor activity of vasopressin. In water-replete dogs, vasopressin blockade caused no significant changes in mean arterial pressure, heart rate, plasma renin activity (PRA), or plasma corticosteroid concentration. In the same dogs following 48-h water deprivation, vasopressin blockade increased heart rate from 85 +/- 6 to 134 +/- 15 beats/min (P less than 0.0001), increased cardiac output from 2.0 +/- 0.1 to 3.1 +/- 0.1 1/min (P less than 0.005), and decreased total peripheral resistance from 46.6 +/- 3.1 to 26.9 +/- 3.1 U (P less than 0.001). Plasma renin activity increased from 12.4 +/- 2.2 to 25.9 +/- 3.4 ng ANG I X ml-1 X 3 h-1 (P less than 0.0001) and plasma corticosteroid concentration increased from 3.2 +/- 0.7 to 4.9 +/- 1.2 micrograms/dl (P less than 0.05). Mean arterial pressure did not change significantly. When the same dogs were again deprived of water and pretreated with the beta-adrenoceptor antagonist propranolol, the heart rate and PRA responses to the antagonists were attenuated and mean arterial pressure decreased from 103 +/- 2 to 91 +/- 3 mmHg (P less than 0.001). These data demonstrate that vasopressin plays an important role in blood pressure regulation during water deprivation in conscious dogs.


1978 ◽  
Vol 55 (s4) ◽  
pp. 301s-303s ◽  
Author(s):  
S. F. Wong ◽  
M. I. Mitchell ◽  
V. Robson ◽  
R. Wilkinson

1. Plasma renin activity, response to saralasin and exchangeable sodium have been measured in 43 patients with early renal disease. 2. Blood pressure was directly proportional to plasma renin activity. However, mean plasma renin activity was lower in patients with renal disease than in normal controls. 3. Blood pressure fell in response to saralasin infusion in proportion to the pre-infusion plasma renin activity. 4. Exchangeable sodium in hypertensive patients with renal disease did not exceed that in normotensive patients in contrast to earlier reports. Discrepancies may arise from the difficulty in interpreting measured exchangeable sodium in relation to body build.


1978 ◽  
Vol 55 (s4) ◽  
pp. 307s-309s ◽  
Author(s):  
G. Leonetti ◽  
Laura Terzoli ◽  
Carla Sala ◽  
C. Bianchini ◽  
Laura Sernesi ◽  
...  

1. The pressor role of renin stimulated by chronic diuretic therapy has been assessed in 31 patients with essential hypertension by infusing the angiotensin II antagonist, saralasin, immediately before and at the end of 2 weeks' treatment with the diuretic, chlorthalidone. 2. Under diuretic therapy the change in blood pressure caused by saralasin was found to be correlated to plasma renin activity values, in such a way that small pressor responses were again observed in patients whose renin was mildly stimulated by the diuretic, whereas a marked depressor response occurred in patients whose renin was markedly increased. 3. On the other hand, the hypotensive effect of chlorthalidone was correlated to values of plasma renin activity under diuretic therapy in an opposite direction: indeed little or no decrease and sometimes an increase in blood pressure were observed in patients with marked renin activation by diuretic therapy. 4. It is concluded that stimulation of renin release by chronic diuretic therapy can be considered a factor limiting the hypotensive activity of diuretic drugs.


1988 ◽  
Vol 254 (3) ◽  
pp. H509-H516 ◽  
Author(s):  
M. Burnier ◽  
B. Waeber ◽  
J. F. Aubert ◽  
J. Nussberger ◽  
H. R. Brunner

A nonhypotensive dose of endotoxin was administered to normal conscious rats to evaluate the vascular and humoral effects of endotoxemia per se. Mean blood pressure and heart rate remained stable during the 45 min infusion of Escherichia coli endotoxin (0.01 mg/min). However, a marked increase in plasma renin activity (4.2 +/- 0.48 vs. 30.2 +/- 6 ng.ml-1.h-1, mean +/- SE, P less than 0.01), plasma epinephrine (0.112 +/- 0.04 vs. 1.71 +/- 0.5 ng/ml, P less than 0.01), and plasma norepinephrine (0.269 +/- 0.028 vs. 1.3 +/- 0.2 ng/ml, P less than 0.001) was observed during infusion in endotoxin-treated rats when compared with the vehicle-treated animals. In addition, the blood pressure response to exogenous norepinephrine was significantly reduced during nonhypotensive endotoxemia. Significant changes in regional blood flow distribution, as assessed by radiolabeled microspheres, were observed in endotoxemic rats; in particular a decrease in renal blood flow (7.39 +/- 0.43 vs. 5.97 +/- 0.4 ml.min-1.g-1, P less than 0.05) and an increase in coronary blood flow (5.01 +/- 0.38 vs. 6.44 +/- 0.33 ml.min-1.g-1, P less than 0.01) were found. The role of prostaglandins in the vascular and humoral alterations induced by nonhypotensive endotoxemia was also examined. Pretreatment with indomethacin (5 mg) prevented the increase in plasma renin activity as well as plasma catecholamine levels. On the contrary, the decreased vascular reactivity and the reduction in renal blood flow observed during endotoxemia were not affected by prostaglandin synthesis inhibition. Thus significant vascular and humoral changes have been found during endotoxemia even in absence of hypotension.(ABSTRACT TRUNCATED AT 250 WORDS)


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