Effect of angiotensin II and of an Angiotensin II Analogue (Sar1-Ile8-Angiotensin II) on Blood Pressure, Plasma Aldosterone and Plasma Renin Activity in the Dog

1974 ◽  
Vol 48 (s2) ◽  
pp. 41s-44s
Author(s):  
R. Beckerhoff ◽  
G. Uhlschmid ◽  
W. Vetter ◽  
H. Armbruster ◽  
J. Nussberger ◽  
...  

1. The effect of infusions of equimolar doses of angiotensin II (AII) and of the angiotensin analogue Sar1-Ile8-angiotensin II on arterial blood pressure, plasma aldosterone and plasma renin activity were compared in normal anaesthetized dexamethasone suppressed dogs. 2. Angiotensin II induced a significant increase of blood pressure and of plasma aldosterone whereas plasma renin activity decreased. The blood pressure was only slightly affected by large doses of the analogue. Plasma aldosterone, however, increased and plasma renin activity decreased. These changes were significant but less pronounced than after the infusions of angiotensin II. Plasma aldosterone remained high and renin activity low for 40 min after the infusions of the analogue. 3. The results suggest a strong agonistic potency of Sar1-Ile8-angiotensin II at the adrenal and renal angiotensin receptors, and that it is almost ineffective at the vascular receptors. The inhibition of renin secretion by angiotensin seems not to be related to its vasoconstrictive activity.

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.


1982 ◽  
Vol 63 (s8) ◽  
pp. 195s-197s ◽  
Author(s):  
T. Kono ◽  
F. Oseko ◽  
F. Ikeda ◽  
H. Imura ◽  
M. C. Khosla ◽  
...  

1. When the angiotensin II-(4-8)-pentapeptide was infused intravenously at rates of 0.31-5.55 nmol min−1 kg−1 for 10–120 min into five normal men or two patients with Bartter's syndrome, no significant change was observed in blood pressure, plasma renin activity and plasma aldosterone, and the lowest dose did not inhibit the captopril-induced increase in plasma renin activity in the normal men. 2. An intravenous infusion of the pentapeptide at 9–0 nmol min−1 kg−1 for 15 min significantly raised blood pressure in the five normal men but not in patients with Bartter's syndrome. Blood pressure returned to the pre-treatment level 60 min after the cessation of the infusion in the normal men. 3. At the same dose level none of the seven subjects examined showed any significant change in plasma renin activity and plasma aldosterone. 4. Angiotensin II-(5-8)-tetrapeptide was infused intravenously into one of the normal men at a rate of 41.5 nmol min−1 kg−1 for 15 min, but it caused no significant change in blood pressure, plasma renin activity and plasma aldosterone. 5. These results suggest that the pentapeptide and probably the tetrapeptide do not possess renin-suppressing and steroidogenic actions in man but that the former peptide does elicit a modest pressor action with a prolonged duration.


1979 ◽  
Vol 57 (s5) ◽  
pp. 371s-373s ◽  
Author(s):  
Connie S. McCaa ◽  
H.G. Langford ◽  
W. C. Cushman ◽  
R. E. McCaa

1. The response of arterial blood pressure, plasma renin activity and plasma aldosterone concentration to inhibition of angiotensin I converting enzyme (kininase II) with captopril has been studied in patients with severe, treatment-resistant, malignant hypertension. 2. Nine patients with a past history of severe hypertension, supine diastolic blood pressure &gt; 120 mmHg before conventional antihypertensive therapy and resistant to conventional antihypertensive therapy were studied. 3. Captopril administration resulted in a marked decrease in arterial blood pressure and plasma aldosterone concentration and an increase in plasma renin activity. 4. Although arterial blood pressure remained significantly below the values observed during the control period, pressure did tend to increase again after 3 days. Addition of hydrochlorothiazide kept arterial pressure significantly below pretreatment control values.


1978 ◽  
Vol 89 (1) ◽  
pp. 132-141 ◽  
Author(s):  
Ikuo Saito ◽  
Takao Saruta ◽  
Toyohisa Eguchi ◽  
Kazuoki Kondo ◽  
Ryuichi Nakamura ◽  
...  

ABSTRACT To evaluate the role of angiotensin III in the control of blood pressure, plasma aldosterone and plasma renin activity (PRA), the pressor, steroidogenic and PRA-suppressing effect of angiotensin III was studied in rabbits with or without simultaneous constant infusion of Ile7-angiotensin III, an analogue of angiotensin III, or Sar1Ala8-angiotensin II, an analogue of angiotensin II, and compared with the effect of angiotensin II. Infusion of 30 ng/kg/min of angiotensin III or angiotensin II produced a twofold increase in plasma aldosterone. Pressor response to angiotensin III was approximately one tenth of that of angiotensin II. Infusion of angiotensin II suppressed the PRA significantly, while infusion of angiotensin III did not suppress it. Angiotensin II or angiotensin III induced-increase in plasma aldosterone was attenuated by the pretreatment with either Ile7-angiotensin III or Sar1Ala8-angiotensin II. Pressor or PRA-suppressing action of angiotensin II was unaffected by the pre-treatment with Ile7-angiotensin III, while it was significantly inhibited by pre-treatment with Sar1Ala8-angiotensin II. This study indicates that angiotensin III or angiotensin III analogues affect the adrenal glands selectively and suggests that there are differences between the receptor sites for angiotensins in vascular smooth muscle, kidney and those in the adrenal cortex.


1976 ◽  
Vol 51 (s3) ◽  
pp. 147s-150s
Author(s):  
R. Beckerhoff ◽  
G. Uhlschmid ◽  
W. Vetter ◽  
W. Siegenthaler

1. The effects of infusions of equimolar doses of angiotensin II (AII) and of Des1-angiotensin II (heptapeptide) on plasma renin activity, blood pressure and plasma aldosterone were compared in normal anaesthetized dexamethasone-suppressed dogs. 2. Plasma renin activity was equally suppressed by both compounds. The increase in blood pressure induced by the heptapeptide averaged 43–62% of the increase during AII infusions. No significant differences in aldosterone increase were observed between AII and the heptapeptide. Plasma aldosterone, however, dropped significantly faster in heptapeptide-treated dogs after the end of the infusions. 3. Sar1-Ala8-angiotensin II (saralasin, 400 pmol min—1 kg—1) suppressed plasma aldosterone that was stimulated by heptapeptide (20 pmol min—1 kg—1) completely. The same angiotensin antagonist had only a moderate effect on plasma aldosterone stimulated by AII. After stopping the antagonist infusion, plasma aldosterone rose significantly higher in dogs infused with AII than in those receiving the heptapeptide. 4. The results demonstrate differences between the effects of AII and the heptapeptide both on blood pressure and on plasma aldosterone. They do not support the hypothesis that the heptapeptide may be the main mediator of aldosterone secretion.


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