Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.23.15 (renin)
 35,795 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Propranolol administration in the hypoxic model of acute renal failure (ARF) in rats has reduced plasma renin activity (PRA) and uraemia as compared to untreated controls. P113 has no effect on uraemia but increased PRA in ARF. A combination of both drugs is no more effective in reducing uraemia than propranolol alone. These results support the view that beta-adrenergic blockade by propranolol reduces the severity of ARF by preventing the post-hypoxic release of renin.
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PMID:beta-Adrenergic blockade reduces the severity of acute renal failure in rats. 0 58

The effectiveness of beta-adrenergic blockade in preventing acute renal failure (A.R.F.) in rats was studied in the hypoxia model produced by unilateral nephrectomy and clamping of the contralateral renal artery for 70 minutes. Beta-adrenergic blockade effectively reduced the severity of A.R.F. in this experimental model. Treatment with a combination of propranolol and a synthetic angiotensin-II competitive inhibitor (P113) produced no further improvement. These results are consistent with the view that intrarenal release of renin is to some extent involved in the pathogenesis of A.R.F.
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PMID:Reduction in severity of acute renal failure in rats by beta-adrenergic blockade. 4 48

The effect of infusion of the angiotensin II antagonist P113 on blood-pressure (B.P.) has been studied in 10 patients with various forms of hypertension under four different conditions: before and after salt depletion and with or without propranolol treatment. The fall in B.P. after P113 infusion significantly correlated with log P.R.A. (plasma-renin activity), irrespective of diagnosis or treatment. P113 infusion caused a consistent fall in B.P. only after sodium depletion. The changes in B.P. after P113 infusion and those induced by propranolol correlated only during sodium depletion, when P.R.A. values rose. It is concluded that sodium depletion induced "renin dependency" of B.P. in all patients. The decrease in B.P. renin dependency after propranolol therapy suggests that suppression of P.R.A. is one of the antihypertensive mechanisms underlying the action of this drug.
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PMID:Renin dependency of blood-pressure. Analysis by angiotensin II antagonist P113 in hypertensive patients treated with salt depletion and propranolol. 5 53

This study was designed to ascertain whether renal vascular angiotensin receptors differ from other systemic angiotensin receptors and whether, on that basis, antagonists with greater specificity for the renal vasculature can be defined. Femoral and renal blood flow and their responses to angiotensin II (AII) and its heptapeptide analogue, 1-des Asp AII (AIII), were measured with an electromagnetic flowmeter in 26 dogs. For the kidney, the threshold doses of AII and AIII were identical (2.5+/-0.27 vs. 2.3+/-0.35 pmol/100 ml renal blood flow, with similar dose-response curves. In contrast, AII had a greater pressor effect (P less than 0.001) and produced more femoral vasoconstriction (P less than 0.001) than AIII. All four antagonists studied (1-Sar, 8-Ala AII [P113]; 8-Ala AII; 1-des Asp, 8-Ala AII; 1-des Asp, 8-Ile AII) induced parallel shifts in the renal blood flow response to AII and AIII. P113 induced greater blockade than 8-Ala AII (P less than 0.001) which, in turn, was more effective than 1-des Asp, 8-Ala AII (P less than 0.001). 1-des Asp, 8-Ile AII was as effective as P113. Each analogue induced an identical inhibition of the renal vascular response to AII and AIII. In addition, AII and AIII induced cross-tachyphylaxis. All lines of evidence suggested that AII and AIII act on a single receptor in the kidney, which differs at least functionally from other systemic vascular receptors. The possibility that heptapeptide analogues represent angiotensin antagonists with greater specificity for the renal vasculature was pursued in a model in which the renin-angiotensin system is activated. Acute, partial thoracic inferior vena caval occlusion was induced in an additional 16 dogs. P113 induced progressive, dose-related hypotension and a limited increase in renal blood flow in this model. The 1-des Asp, 8-Ile AII analogue, conversely, induced a consistent, larger, dose-related renal blood flow increase, with significantly less hypotension over a wide dose range. We conclude that the renal vascular receptor differs sufficiently from systemic angiotensin receptors that heptapeptide analogues of AII will be useful in exploring angiotensin's role in states characterized by disordered renal perfusion and function.
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PMID:Angiotensin antagonists with increased specificity for the renal vasculature. 19 Feb 70

Vasodilating antihypertensive drugs induce hypotension with reflex tachycardia, renin release, and fluid and electrolyte retention. Propranolol can impair this renin release. The studies described here were designed to determine the hemodynamic role of vasodilatory drug-induced renin release and inhibition thereof by propranolol in two animals models, the unanesthetized, normotensive and the unanesthetized, genetically hypertensive rat. In studies with normotensive rats, propranolol impaired renin release and tachycardia resulting from hydralazine and minoxidil and potentiated their hypotensive action. Two additional interventions against the renin-angiotensin system were used in evaluating the mechanism of this potentiation. One was removal of the renin source by nephrectomy, and the second was blockade of angiotensin's vasoconstrictor action using a selective angiotensin antagonist, saralasin (1-Sar-8-Ala-angiotensin II (previously known as P113)).. Both interventions potentiated vasocilatory drug hypotension, as did propranolol, but did not prevent reflex tachycardia. When combined with saralasin propranolol did not add to protentiation by this peptide. A similar pattern of blood pressure decrement and potentiation was seen in genetically hypertensive rats when propranolol or saralasin treatment preceded hydralazine. Propranolol was demonstrated to block hydralazine-induced increases in serum renin activity in genetically hypertensive rats. We conclude that hypotensive potentiation of vasocilating drugs by propranolol in these animal models is mediated to a large extent by impairment of renin release. Persistence of hypotensive tachycardia after nephrectomy and after saralasin in normotensive rats suggests the irrelevance of angiotensin's central nervous system stimulation to this cardiac effect. Clinical studies are underway to quantify the potential importance of this beneficial drug interaction in man.
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PMID:Altered renin release and propranolol potentiation of vasodilatory drug hypotension. 23 25

Intrarenal infusion of Sar1-Ala8 angiotensin II(P113), a competitive antagonist of angiotensin II, failed to reverse or prevent the decreased ipsilateral renal blood flow and increased renal resistance characteristic of chronic unilateral ureteral occlusion and did not significantly alter plasma renin activity in the chronic state. Thus, angiotensin II does not appear to play a significant role in the hemodynamic response to unilateral ureteral occlusion.
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PMID:The role of intrarenal angiotensin II in the hemodynamic response to unilateral obstructive uropathy. 84 4

Acute renal failure induced in Charles River rats by right nephrectomy and left renal artery clamping for 70 min, constantly produced high blood urea and serum creatinine levels 24 h following the experimental procedure. The intravascular administration of propranolol in different doses persistently alleviated the severity of uremia seen on the following day. The optimum dose in this experimental set-up was 1 mg/kg/h. The mean blood urea level was 237 +/- 15.5 (SEM) mg% in the saline-treated controls and 116 +/- 16 mg% in the group treated with propranolol 1 mg/kg/h. P113 alone and prostaglandin A1 alone were not effective in alleviating the ARF. The combination of P113 and propranolol produced the same amount of alleviation in uremia as propranolol alone. The PRA was low in the propranolol-treated rats and high in the group which received both P113 and propranolol, even though alleivation of ARF was produced in both of these groups. The mechanism by which the beta-adrenergic blockade produced by propranolol alleviates the anoxic type of acute renal failure is unknown. However, it does not seem to act through the suppression of renin release from the kidney.
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PMID:Alleviation of anoxic experimental acute renal failure in rats by beta-adrenergic blockade. 89 66

1 Three normal subjects were infused with Sar1-ala8-angiotensin II (Saralasin, P113) whilst on a high sodium (200 mEq + normal diet) and a low sodium (10 mEq diet) intake. 2 On the high sodium intake when angiotensin II and plasma renin activity (PRA) were suppressed, P113 infusion (5-10 mug kg-1 min-1) caused a slight rise in BP and a marked drop in urine flow and sodium excretion, with a fall in glomerular filtration rate, and effective renal plasma flow. 3 On the low sodium intake, when angiotensin II and PRA were increased, P113 infusion (5-10 mugkg-1 min-1) caused no change in blood pressure, urine flow or sodium excretion. However, when P113 was infused at an incremental rate starting at 0.25 mug kg-1 min-1 there was a fall in standing BP, which was maximal at an infusion rate of 1 mug kg-1 min-1, and this fall in standing BP was largely abolished as the rate of infusion was increased to 10 mug kg-1 min -1. 4 These results show firstly that angiotension II is involved in maintaning standing blood pressure during dietary sodium depletion in normal man and secondly that P113 does have agonist as well as antagonist activity in normal man, the effect depending on the level of angiotension II and sodium intake. When looking for angiotensin II mediated hypertension it may ne important to use an incremental rate of infusion of P113 as the agonist activity of larger doses may mask its hypotensive action.
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PMID:Agonist and antagonist effects of Sar1-ala8--angiotensin II in salt-loaded and salt-depleted normal man. 97 74

In order to study the role of renin in regulating blood pressure in normotensive states, saralasin (P113) was infused into normal subjects and patients with cirrhosis of the liver and ascites. In normal subjects on a normal sodium intake, P113 infusion had no effect on blood pressure. Only after the combined stress of a low sodium diet and the upright position did P113 lower the blood pressure. In two of the six cirrhotic patients, P113 caused a significant decrease in BP in the supine position. There was no consistent effect of the P113 infusion on plasma aldosterone or plasma renin activity in the normal or cirrhotic subjects.
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PMID:The role of renin in the control of blood pressure in normotensive man. 101 62

To test the role of the renin/angiotensin system in aldosterone regulation, Sar1-Ala8-angiotensin II (P113) was infused into the arterial blood supply of transplanted adrenal glands in conscious sheep. Effects on the aldosterone response to infused angiotensin II and III in sodium replete sheep were compared with effects in sodium deficiency. Adrenal arterial infusion of P113 up to 1,000 mug/h for 1-2h did not consistently alter the high aldosterone secretion rates of sodium-deficient sheep. However, infusion of P113 at 10 mug/h or more abolished aldosterone responses to angiotensin II infusion that caused high physiological blood levels of angiotensin II. These results are against the proposal of a primary proportional causal relationship between blood angiotensin II concentration and aldosterone secretion rate in sodium deficiency. They are also against the possibility that such a primary role is played by blood-borne angiotensin III.
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PMID:Effect of adrenal arterial infusion of saralasin (P113) on aldosterone secretion. 101 70


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