Pharmacological and genetic evidence that cathepsin B is not the physiological activator of rodent prorenin

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.

1975 ◽  
Vol 48 (2) ◽  
pp. 147-151
Author(s):  
C. S. Sweet ◽  
M. Mandradjieff

1. Renal hypertensive dogs were treated with hydrochlorothiazide (8−2 μmol/kg or 33 μmol/kg daily for 7 days), or timolol (4.6 μmol/kg daily for 4 days), a potent β-adrenergic blocking agent, or combinations of these drugs). Changes in mean arterial blood pressure and plasma renin activity were measured over the treatment period. 2. Neither drug significantly lowered arterial blood pressure when administered alone. Plasma renin activity, which did not change during treatment with timolol, was substantially elevated during treatment with hydrochlorothiazide. 3. When timolol was administered concomitantly with hydrochlorothiazide, plasma renin activity was suppressed and blood pressure was significantly lowered. 4. These observations suggest that compensatory activation of the renin-angiotensin system limits the antihypertensive activity of hydrochlorothiazide in renal hypertensive dogs and suppression of diuretic-induced renin release by timolol unmasks the antihypertensive effect of the diuretic.


1992 ◽  
Vol 262 (3) ◽  
pp. R524-R529 ◽  
Author(s):  
N. D. Binder ◽  
D. F. Anderson

We examined the relationship between acute reductions in renal perfusion pressure, as approximated by femoral arterial blood pressure, and plasma renin activity in the uninephrectomized fetal lamb. Renal perfusion pressure was reduced and maintained at a constant value by controlled partial occlusion of the aorta above the renal artery. After 15 min of reduced blood pressure, blood samples were taken for determination of plasma renin activity. This protocol was performed 22 times in 11 fetal lambs. Additionally, three of the fetuses were delivered by cesarean section and studied as newborns for the first week of life. In the fetus, there was a linear relationship between log plasma renin activity and femoral arterial blood pressure (P less than 0.01). After birth, the relationship still existed, although it was shifted to the right (P less than 0.0001). We conclude that there is a significant relationship between plasma renin activity and renal perfusion pressure in the fetal lamb, and as early as 1 day after birth, this relationship shifts to the right in the newborn lamb.


1988 ◽  
Vol 119 (2) ◽  
pp. 257-262 ◽  
Author(s):  
Sadao Nakajima ◽  
Hiromichi Suzuki ◽  
Yo Kageyama ◽  
Takashi Takita ◽  
Takao Saruta

Abstract. The effects of atrial natriuretic peptide (ANP) on mean arterial blood pressure, heart rate, plasma renin activity, aldosterone, cortisol, norepinephrine, epinephrine and arginine vasopressin were studied in 6 anuric subjects receiving regular hemodialysis. An iv bolus injection of 8 nmol of ANP followed by infusion at 32 pmol·kg−1·min−1 for 1 h in the pre- and posthemodialysis period was performed. Basal plasma ANP was higher before than after hemodialysis. ANP administration produced a reduction in mean arterial blood pressure accompanied by an elevation of norepinephrine and of plasma renin activity (from 2.49 ± 0.52 to 3.39 ± 0.85 nmol·l−1·h−1 predialysis and from 2.78 ± 0.71 to 3.15 ± 0.86 nmol·l−1·h−1 postdialysis, respectively, mean ± sem; P < 0.05). Plasma aldosterone and cortisol were significantly decreased. Plasma epinephrine and AVP remained unchanged. These hemodynamic and hormonal changes were similar in the pre- and the postdialysis period. These results suggest that 1) ANP causes a fall in mean arterial blood pressure, which in turn induces reflex tachycardia and activation of the sympathetic nervous system without diuresis; 2) the activated sympathetic nervous system as reflected in elevation of plasma norepinephrine may increase plasma renin activity; 3) reduced plasma aldosterone is not influenced by enhancement of the reninangiotensin system; therefore, 4) reduction of plasma aldosterone as well as cortisol is probably due to direct action of ANP, and finally 5) AVP had no direct relation with ANP administration.


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. 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.


1976 ◽  
Vol 41 (3) ◽  
pp. 323-327 ◽  
Author(s):  
K. J. Kosunen ◽  
A. J. Pakarinen ◽  
K. Kuoppasalmi ◽  
H. Adlercreutz

Plasma renin activity (PRA), angiotensin II, and aldosterone levels, arterial blood pressure, and heart rate of six male students were investigated during and after heat stress in a sauna bath. Increased PRA, angiotensin II, and aldosterone levels were found both during and after sauna. The greatest mean increases in PRA (94.9 +/- 10.4% SE, P less than 0.005) and angiotensin II (196 +/- 54.7% SE, P less than 0.02) were observed at the end of the heat stress (at 20 min), and that in plasma aldosterone (505 +/- 209% SE, P less than 0.02) 30 min after the sauna. The heart rate roughly doubled during the heat stress and there was a transient increase followed by a decrease in systolic blood pressure and a decrease in diastolic blood pressure. This study demonstrates that intense heat stress can cause remarkable changes in the three main components of the renin-angiotensin-aldosterone system.


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)


1992 ◽  
Vol 82 (4) ◽  
pp. 389-395 ◽  
Author(s):  
C. Stonier ◽  
J. Bennett ◽  
E. A. Messenger ◽  
G. M. Aber

1. The effect of oestradiol alone and in combination with indomethacin on blood pressure, erythrocyte cation concentration and Na+−K+ flux has been studied in adult female normotensive and spontaneously hypertensive rats. 2. Oestradiol alone resulted in a significant decrease in blood pressure in spontaneously hypertensive rats (from 165.3 ± 3.9 to 146.4 ± 2.7 mmHg, P < 0.001), whereas it induced a significant increase in normotensive rats (from 111.8 ± 1.8 to 124.1 ± 3.6 mmHg, P < 0.001). When indomethacin and oestradiol were administered simultaneously or when indomethacin was given alone, no change in blood pressure occurred in spontaneously hypertensive rats (158.6 ± 6.9 and 159.8 ± 6.2 mmHg, respectively). 3. The fall in blood pressure induced by oestradiol in spontaneously hypertensive rats was associated with significant reductions in erythrocyte K+ concentration (from 127.4 ± 1.2 to 116.9 ± 1.7 mmol/l of cells, P < 0.001), in erythrocyte Na+ concentration (from 14.3 ± 0.8 to 13.0 ± 0.6 mmol/l of cells, P < 0.02), in ouabain-sensitive erythrocyte Na+ flux (from 17.8 ± 0.3 to 16.0 ± 0.4 mmol h−1 (1 of cells)−1, P < 0.01) and in ouabain-sensitive erythrocyte K+ flux (from 11.4 ± 0.2 to 10.4 ± 0.2 mmol h−1 (1 of cells)−1, P < 0.01). No change in blood pressure, erythrocyte cation concentration or Na+−K+ flux occurred when oestradiol and indomethacin were given together or when indomethacin was administered alone. 4. The hypertensive influence of oestradiol in normotensive rats was unaccompanied by any changes in erythrocyte K+ concentration, erythrocyte Na+ concentration and total, ouabain-sensitive and ouabain-resistant Na+−K+ flux. 5. The divergent changes in blood pressure noted in the two strains occurred despite comparable changes in plasma renin activity after oestradiol, with significant increases in plasma renin activity in normotensive rats (from 16.4 ± 4.2 to 28.4 ± 6.6 ng of angiotensin I h−1 ml−1, P < 0.05) and in spontaneously hypertensive rats (from 28.3 ± 2.7 to 39.5 ± 5.7 ng of angiotensin I h−1 ml−1, P < 0.01). The plasma renin activity in spontaneously hypertensive rats receiving oestradiol or indomethacin and oestradiol were similar with values of 39.5 ± 5.7 and 40.6 ± 5.7 ng of angiotensin I h−1 ml−1, respectively, but were significantly higher than that seen in control animals (28.3 ± 2.7 ng of angiotensin I h−1 ml−1, P < 0.01). Similarly, indomethacin alone induced a significant increase in plasma renin activity in spontaneously hypertensive rats to 35.8 ± 7.6 ng of angiotensin I h−1 ml−1 (P < 0.05). 6. The contrasting effects of oestradiol on blood pressure in the two rat strains occurred without any change in packed cell volume. Likewise, the changes in blood pressure in spontaneously hypertensive rats with either oestradiol alone or in combination with indomethacin occurred without any change in packed cell volume, although indomethacin alone resulted in a significant reduction in packed cell volume (from 30.9 ± 1.6 to 26.8 ± 2.0, P < 0.01). 7. The results suggest that the hypotensive action of oestradiol in spontaneously hypertensive rats might be mediated through its influence on erythrocyte cation concentration and/or the modulation of Na+−K+ flux either directly or via the action of prostanoids.


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