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)

Plasmin noradrenaline concentration after bicycle exercise (200 W for 2 min), compared with base line concentration, was used as an index of sympathetic responsiveness in patients with essential hypertension. Atenolol (JCI 66082, a "cardioselective" beta-blocker) was given in a daily dose of 200 mg to 16 patients for five weeks. This caused a decrease in supine blood pressure of 37/23 and, on standing, of 36/25 mm Hg compared with the placebo period. There was a significant correlation between the ratio of the increase in plasma noradrenaline concentration on exercise over its base line concentration and the subsequent fall in mean arterial pressure (r=0.840; P less than 0.001). There was a less significant correlation between plasma renin concentration and subsequent decrease in mean arterial pressure (r=0.542; P less than 0.05). Administrations of atenolol caused a rise in plasma noradrenaline both on lying and after exercise (P less than 0.0125), and a fall in plasma renin concentration (P less than 0.01). The results suggest that the antihypertensive effect of atenolol is related to the responsiveness of the sympathetic nervous sytem. Adrenergic activity is apparently an important determinant of blood pressure response to beta-blockade.
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PMID:[Sympathetic responsiveness and antihypertensive effect of beta-receptor blockade in essential hypertension: the effect of atenolol (author's transl)]. 1 16

The relationship between sympathetic responsiveness and the blood pressure reduction induced by long-term beta-blockade was assessed in patients with essential hypertension. The increase in plasma noradrenaline concentration during physical exercise was used as an index of sympathetic responsiveness. The cardioselective beta-blocker, atenolol, was given to 16 patients with sustained benign essential hypertension for five weeks at a dose of 200 mg/day. Atenolol induced a marked decrease in blood pressure and pulse rate during recumbency, orthostasis and exercise concomitant with a marked increase in plasma noradrenaline concentration (p less than 0.0125) and a pronounced decrease in plasma renin concentration (p less than 0.01). The ratio of plasma noradrenaline during exercise to the base line concentration correlated significantly with the subsequent decrease in mean arterial blood pressure induced by beta-blockade (r = 0.840; p less than 0.001). A less significant correlation was observed between the plasma renin concentration and the subsequent decrease in mean arterial pressure (r = 0.542; p less than 0.05). The results obtained indicate that sympathetic responsiveness is an important determinant of blood pressure response to beta-blockade induced by atenolol.
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PMID:Sympathetic responsiveness and antihypertensive effect of beta-receptor blockade in essential hypertension. 2 17

Atenolol, a cardioselective beta-blocking drug, was prescribed in doses of 100 mg b.i.d. in 23 patients with essential hypertension. At the end of the first month of treatment with Atenolol we found a significant fall in blood pressure, heart rate and plasma renin activity (P.R.A.). Besides, there existed a relationship between changes in diastolic blood pressure, in mean arterial pressure and initial plasma renin activity, and a relationship between changes in blood pressure and changes in P.R.A. It results from this finding that pretreatment P.R.A. is of predictive value of short-term efficacy of the beta-blocker. This correlation was borderline in 21 patients after a mean of 7 month treatment and could no be found for 12 cases after a mean of 10 month-treatment while the fall in P.R.A. was still significant. It therefore appears that--with reserve of the representativeness of the sample--quantitative relations between the antihypertensive effect of Atenonol and P.R.A. are no longer significant on long-term treatment.
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PMID:Effect of atenolol, a new cardioselective beta-blocker, on plasma renin activity in treatment of hypertension. 30 91

The efficacy of various combinations of atenolol, bendrofluazide, and hydraliazine given twice daily was assessed in a double-blind trial on 39 patients with moderate to severe essential hypertension. Concurrent treatment with all three drugs proved most effective and produced a mean reduction in blood pressure of 43/31 mm Hg. In the dosage used, hydrallazine affected only the diastolic blood pressure, and when added to either bendrofluazide or bendrofluazide plus atenolol it produced a further mean reduction in pressure of 6 mm Hg. Once-daily treatment with atenolol and bendrofluazide was as effective in reducing blood pressure as the same combination given twice daily, and the hypotensive effect was still present at least 24 hours after the last dose of tablets. A combined tablet of atenolol and bendrofluazide taken once daily would be a simple regimen to follow and would provide almost as much hypotensive effect as a twice-daily regimen incorporating a modest dose of hydrallazine. The hypotensive effect of atenolol was equal to that of bendrofluazide on systolic pressure but significantly better than that of bendrofluazide on diastolic pressure. Atenolol reduced plasma renin and urate concentrations but increased plasma potassium levels. The biochemical effects of atenolol, therefore, may be an advantage over those of bendrofluazide when deciding on first-line treatment for essential hypertension.
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PMID:Contribution of atenolol, bendrofluazide, and hydrallazine to management of severe hypertension. 32 48

A double-blind crossover trial was completed in 15 patients with moderate hypertension and the effects of propranolol (Inderal) 80 mg twice a day and atenolol (Tenormin) 100 mg twice a day were assessed on blood pressure, pulse rate and plasma renin activity (PRA), while patients were maintained on 1 cyclopenthiazide tablet (Navidrex K) per day. Both agents caused a significant reduction in blood pressure and pulse rate with patients at rest and during exercise. Plasma renin activity was significantly reduced by both agents in subjects with normal and high renin levels (with PRA 2-8 ng/ml/h and greater than 8 ng/ml/h respectively). Blood pressure responses could not be correlated with renin status or reduction in pulse rate. No adverse effects were attributable to either of the two beta-adrenergic blocking agents and we concluded that a beta1-selective agent, which has the advantage of not aggravating bronchospasm, can replace the non-selective propranolol.
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PMID:Effects of propranolol and atenolol on blood pressure and plasma renin activity in patients with moderate hypertension. 34 73

The antihypertensive effect of atenolol, a new beta 1 receptor blocking agent, was studied in a double blind non cross-over trial in 40 patients (pts) affected by mild to moderately severe essential hypertension with normal plasma renin activity. After a run-in period (15 days) of placebo treatment pts were assigned to two groups. The first (group A) continued placebo treatment for 30 days, the second (Group B) were given atenolol (ICI 66082) 100 mg daily for 30 days also. Atenolol significantly reduced systolic and diastolic blood pressure in recumbent and standing position and heart rate at rest. No significantly changes of the same parameters were observed in group A. Body weight and plasma renin activity was unchanged in both groups. Atenolol treatment never was discharged in order to side effects. These results seem to suggest that atenolol can be an useful drug in the treatment of systemic blood hypertension.
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PMID:[Efficacy and tolerability of a cardioselective beta-blocking drug (atenolol) in the treatment of essential hypertension. A double blind study (author's transl)]. 35 98

In 15 patients with moderate to severe hypertension (WHO II--III) atenolol was evaluated against a thiazide diuretic (bendrofluazide) in a single blind crossover study. Systolic blood pressure values were lowered more efficiently by the diuretic, while diastolic pressure values were significantly better controlled by atenolol. Atenolol and bendrofluazide, by mere addition of the pressure effects of the single components, clearly afforded the best pressure control. Side effects of atenolol were frequent but mild, never causing major concern with the patients or a dropout from the study. Although the pressure response to atenolol was significantly better in the normal and high renin group of patients, there was no statistically significant correlation between the reduction in plasma renin and blood pressure induced by atenolol. In turn, the pressure response to the diuretic was significantly better in low renin than in normal and high renin patients.
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PMID:[Atenelol and bendrofluazide in the treatment of medium and severe hypertension (preliminary report)]. 37 99

The effects on arterial pressure of saralasin and short-term (seven days) administration of the cardioselective beta-blocker atenolol were compared in 21 patients with various forms of hypertension. During saralasin administration mean arterial pressure (MAP) decreased by 8.8 +/- 2.1 per cent. Atenolol administration was associated with a MAP fall of 23.6 +/- 2.9 per cent. The change in MAP induced by atenolol was higher than that produced by saralasin (P less than 0.001) and no significant correlation (r = 0.40, P greater than 0.05) between their respective effects was found. These results suggest that the antihypertensive action of atenolol is not related to pre-treatment activity of the renin-angiotensin system as estimated by the hypotensive effect of saralasin. Other mechanisms should be sought in order to explain the effectiveness of this betablocker in hypertensive patients.
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PMID:The renin-angiotensin system and the antihypertensive effect of atenolol in man. 52 65

The non-stimulant cardioselective beta adrenocepter antagonist atenolol has been studied in volunteers in order to define its pharmacokinetic characteristics. Atenolol (100 and 200 mg orally) is rapidly absorbed, reductions in heart rate and systolic pressure being observed in 30 min. The effect persists for up to 8 h. Over 85% of an intravenous dose is excreted in urine within 24 h but only 50% of an oral dose. The bioavailability of approximately 50% is due to reduced absorption. Peak blood levels are observed at 2-4 h and the half life of atenolol given orally is 5-6 h. Atenolol reduces the cardiac response to standing and head-up tilt. It does not reduce circulating levels of renin but slightly impairs the renin response to tilt. Atenolol both orally and intravenously reduces supine diastolic pressure about four hours after administration, the effect persisting for up to 24 h.
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PMID:Studies on the pharmacokinetics and pharmacodynamics of atenolol in man. 65 12

The mechanism of the hypotensive effect during beta-adrenergic blockade in hypertension was studied in 38 patients with renal or essential hypertension using the new cardioselective beta blocker, Tenormin. During 5 weeks hospitalization the patients received first a placebo for 5 to 12 days, then a 75 mg. dose of Tenormin was given daily for 1 week, and thereafter the dose was doubled weekly as necessary up to 600 mg. daily. The blood pressure decreased from 180 +/- 26.2/118. "/- 13.6 mm. Hg on placebo to 151 +/-25.5/96 +/-13.8 mm. Hg during the final hospitalization period on Tenormin (600 mg. daily). Six patients developed fluid retention and as this occurred blood pressure control was lost. A subsequent follow-up on an outpatient basis of 15 of the patients showed that when the active drug was replaced by a placebo blood pressure rose again, confirming that the initial fall in blood pressure was a genuine effect. Multistage bicycle ergometer exercise tests were performed at weekly intervals to test the degree of beta blockade and indicated that this was nearly complete when a dose of 600 mg. per day was used. A significant correlation between the hypotensive effect and the degree of beta blockade, assessed by exercise tachycardia, was observed. A slight but statistically significant decrease (26 per cent) was observed in the plasma renin concentration, measured recumbent in the morning. This decrease was, however, not correlated with the hypotensive effect of the drug. Although the cardiac output decreased significantly (from 5.5 +/-1.7 to 4.3 +/- 1.1 L per minute, p less than 0.001), no correlation was found in individual patients between the cardiac output and the blood pressure decrease. On the other hand, for the total group of catheterized patients (n = 28) the calculated total peripheral resistance did not change significantly. Yet a significant correlation was found between the changes in total resistance and the hypotensive effect. This suggests that the reaction of the peripheral vessels rather than the cardiac output decrease determines whether the drug will produce a major decrease of blood pressure in patients with hypertension.
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PMID:Mechanism of hypotensive effect during betaadrenergic blockade in hypertensive patients. 77 42


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