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

The hemodynamic effects of separate and combined intravenous administration of the vasopressin (AVP) V1-receptor antagonist SK&F 100273 (10 micrograms/kg) and the angiotensin I converting enzyme inhibitor captopril (20 mg + 1 mg/h) were studied in 12 sheep during stable halothane anesthesia (1.5% end-tidal conc.). The separate blockade of either V1-receptors or angiotensin II (ANG II) synthesis induced a small (7-10%), but significant, fall in mean systemic arterial pressure (MSAP), whereas the combined treatment caused a 30% reduction in blood pressure. The changes in systemic vascular resistance paralleled those of the MSAP. Consequently, the cardiac output was largely unaffected by the interference with AVP effects and/or ANG II synthesis. The halothane anesthesia effectively increased the plasma levels of AVP and ANG II, and plasma renin activity without any relation to changes in MSAP. When either the AVP effects or ANG II synthesis were blocked separately, there was a slight tendency for a compensatory increase of the unimpeded hormonal system. It is concluded that halothane anesthesia increases the plasma levels of AVP and ANG II in sheep, and that the maintenance of the arterial pressure is dependent on the concurrent vasopressor effects of the two hormones in this situation.
 ...
PMID:Hemodynamic effects of vasopressin antagonism and angiotensin I converting enzyme inhibition during halothane anesthesia in sheep. 154 32

Endothelin-1 (ET-1), a potent vasoconstrictor peptide synthesized by the vascular smooth muscle endothelium, has been previously shown to produce a sustained, salt-sensitive elevation in mean arterial pressure when chronically infused over a 7-day period into male Sprague-Dawley rats. In addition to other physiological actions, ET-1 has been shown to have potent effects on various renal functions, including renin production. Activation of the renin-angiotensin system, therefore, may contribute to the pressor response induced by ET-1. In this investigation, captopril ([2S]-1-[3-mercapto-2-methylpropionyl]-L-proline), a sulfhydryl-containing angiotensin I converting enzyme inhibitor, was chronically administered to endothelin-infused rats to elucidate the role of the renin-angiotensin system in this animal model of hypertension. Rats were catheterized, housed in metabolic cages, and maintained on a fixed 6.0 meq.day-1 sodium intake throughout the experiment, with daily measurements taken of mean arterial pressure, heart rate, water intake, urine output, and urinary sodium and potassium excretions. Infusion of ET-1 alone at a rate of 5.0 pmol.kg-1.min-1 for 7 days was associated with a significant and sustained increase in mean arterial pressure; concomitant chronic administration of captopril in another group of rats at a rate of 1.0 mg.kg-1.hr-1 prevented the ET-1-induced hypertension. In an additional study, however, increases in plasma angiotensin II concentration were not observed in rats administered ET-1 alone at 5.0 pmol.kg-1.min-1. These results indicate that endothelin-induced hypertension may involve stimulation of the renin-angiotensin system but not an increase in circulating angiotensin II concentration.
 ...
PMID:Captopril prevents chronic hypertension produced by infusion of endothelin-1 in rats. 159 67

Hypertension was produced in cynomolgus monkeys by reducing blood flow to the left kidney by 60% via renal artery stenosis (2-kidney, 1-clip). Significant increases in mean arterial blood pressure (MABP) were observed within two to three weeks. Maximum increase (from 95 +/- 6 mmHg to 130 +/- 7 mmHg) occurred at about four to six weeks following renal artery stenosis and was sustained for more than 24 weeks. Plasma renin activity (PRA) was elevated concomitantly with the increase in MABP. PRA was raised to 42 +/- 3 ng angiotensin I/ml/hr six weeks after renal artery stenosis from a control PRA of 3 +/- 0.7 ng angiotensin I/ml/hr. At six months post renal artery stenosis, PRA was 33.4 +/- 4.2 ng angiotensin I/ml/hr. The angiotensin II (AII) receptor antagonist saralasin, the angiotensin I converting enzyme inhibitor captopril, and the renin inhibitor CGP 38,560 produced sustained reductions in MABP. The antihypertensive response to the renin inhibitor CGP 38,560 was associated with a reduction in PRA of greater than 99%, and a greater than 90% reduction in immunoreactive AII. These studies demonstrate that high-renin hypertension can be induced in the cynomolgus monkey. This pathological model provides a useful method for investigating the antihypertensive effects of agents which antagonize the renin-angiotensin system in a nonhuman primate.
 ...
PMID:Development of a high renin model of hypertension in the cynomolgus monkey. 176 Aug 94

To study the effects of a novel angiotensin I converting enzyme inhibitor (ACEI) on hypertension-induced cardiac hypertrophy, benazepril hydrochloride (CGS 14824 A, CAS 86541-74-4) at the dose of 3 and 10 mg/kg/d p.o. was administered to spontaneously hypertensive rats from 4 to 16 weeks of age. In addition to suppression of developing blood pressure, benazepril hydrochloride reduced both the wet weights of whole heart and left ventricle dose-dependently and significantly. Benazepril hydrochloride had no effect on hydroxyproline concentration and content or protein concentration in the left ventricle, whereas is reduced the total protein content dose-dependently. Serum ACE activity was significantly reduced at 10 mg/kg/d of benazepril hydrochloride, but renin activity, aldosterone and noradrenaline concentration in serum were not changed. From the microscopic findings of the left ventricle, benazepril hydrochloride reduced the myocardial hypertrophy significantly. From these results, benazepril hydrochloride seems to suppress the increase in volume load by acting through the renin-angiotensin-aldosterone system, and dose not seem to cause a significant reflex of catecholamine which often occurs with peripheral vessels dilation. Thus, benazepril hydrochloride may be expected to suppress cardiac hypertrophy in patients with hypertension.
 ...
PMID:Effect of benazepril hydrochloride on cardiac hypertrophy in spontaneously hypertensive rats. 183 66

We examined the possible involvement of angiotensin II in the modulation of circulating norepinephrine produced by acute sodium restriction in essential hypertensive patients (n = 18). Sodium restriction potentiated plasma level of norepinephrine in parallel with an increased plasma renin activity (r = 0.81, F = 31.2, p less than 0.05 given by the percent changes). An intravenous infusion of sarcosine-1, isoleucine-8 angiotensin II produced a significant fall in mean arterial pressure (-6 +/- 2 mmHg, p less than 0.05) in patients on sodium restriction but not before sodium restriction, while the infusion of the antagonist produced a greater decrease (p less than 0.05) in plasma norepinephrine with sodium restriction (-158 +/- 23 pg/ml, p less than 0.05) when compared to that obtained before sodium restriction (-91 +/- 11 pg/ml, p less than 0.05). A single oral administration of an angiotensin I converting enzyme inhibitor, captopril caused a greater fall (p less than 0.01) in mean arterial pressure after sodium restriction (-32 +/- 3 mmHg, p less than 0.05) compared to that given before (-21 +/- 3 mmHg, p less than 0.05). However, sodium restriction did not affect the magnitude of reflex increase in plasma norepinephrine to hypotension evoked by captopril (from +88 +/- 16 pg/ml to +87 +/- 17 pg/ml; p greater than 0.05). It can be interpreted that acute sodium depletion results in a substantial contribution of angiotensin II to the expression of hyperadrenergic activity.
 ...
PMID:Angiotensin II mediates hyperadrenergic activity evoked by sodium restriction in essential hypertension. 188 54

In the present study we examined whether the angiotensin I converting enzyme inhibitor, captopril, would protect stroke-prone spontaneously hypertensive rats (SHRSP) from stroke and renal pathology over a 26-week period. In the control group of six untreated SHRSP fed Stroke-Prone Rodent Diet and 1% NaCl drinking solution, all animals developed severe hypertension and stroke by 16.1 weeks of age. In eight salt-loaded SHRSP treated with oral captopril (50 mg/kg/day) beginning at 8.4 weeks of age, systolic blood pressure was slightly but temporarily suppressed and then continued to rise; by 12 weeks of age systolic blood pressure reached levels of severe hypertension, 240 +/- 8 mm Hg, and did not differ from that of untreated SHRSP. No deaths or brain lesions were noted in captopril-treated SHRSP despite severe hypertension maintained through 26 weeks of age when the study ended. Captopril treatment prevented increases in urinary protein excretion (14 +/- 2 v 63 +/- 16 mg/day at 11.7 weeks of age, P less than .01) and the severe brain, renal, and cardiac vascular lesions observed in untreated SHRSP. When maintained on Stroke-Prone Rodent Diet and saline, plasma renin activity of untreated SHRSP surviving until 14.5 weeks of age was markedly increased (29.1 +/- 9.4 ng Ang I/mL/h) compared with either untreated SHRSP (9.2 +/- 2.5 ng Ang I/mL/h, P less than .01) or Wistar-Kyoto rats (3.5 +/- 1.0 ng Ang I/mL/h, P less than .01) maintained on standard diet and water.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Therapeutic benefit of captopril in salt-loaded stroke-prone spontaneously hypertensive rats is independent of hypotensive effect. 193 Aug 50

The present study was designed to examine and compare the acute effects of lisinopril (20 mg) and enalapril (10 mg) after a single oral administration on the inhibition of the renin-angiotensin system (RAS) in eight normal subjects. Serum concentration of lisinopril and enalaprilat, an active metabolite of enalapril, reached the respective maximal levels at 6 and 4 hr after administration of the drugs. At 24 hr, the serum concentration of lisinopril was higher than that of enalapril; thus the rate of disappearance of lisinopril was retarded, in comparison to that of enalapril. The reduction of serum angiotensin I converting enzyme (ACE) activity was consistent with the pattern of increase of concentration of the drugs in the serum. However, with these two drugs, the concentration of plasma ANG II was decreased in a similar manner, and it returned to the pretreatment level within 24 hr. Thus, there was no significant difference in ANG II levels throughout the 24 hr-study between the lisinopril and enalapril treatment. The results indicate that a single administration of 20 mg lisinopril and 10 mg enalapril show similar potency for lowering the circulating ANG II level, although lisinopril exerts a more sustained inhibition of serum ACE activity. The measurement of ANG II provides useful informations for evaluating the efficacy of ACE inhibitors for the inhibition of circulatory RAS.
 ...
PMID:A comparison of lisinopril with enalapril by monitoring plasma angiotensin II levels in humans. 196 9

Protein-induced increases in glomerular filtration rate (GFR), termed renal reserve, is said to be abrogated with the onset of renal disease. However, this notion is inconsistent with the results from animal studies which suggest that alterations in protein intake modulate the glomerular hemodynamics in experimental renal disease. Accordingly, 12 normal subjects and 15 patients with renal disease received a protein meal providing 1 g/kg body weight protein. The subjects were pretreated with either placebo or an angiotensin I converting enzyme inhibitor, enalapril. A significant (P less than 0.05) increase in inulin and para-aminohippurate (PAH) clearance was noted in normal subjects as well as in patients with renal disease. The increase in GFR over basal values in normal subjects (28 +/- 9%), patients with moderate renal failure (20 +/- 13%), and advanced renal failure (21 +/- 14%) was not different. Plasma renin activity was unchanged following protein meal in the placebo studies although it increased following enalapril administration. Enalapril pretreatment did not alter the glomerular vasodilation and hyperfiltration following protein meal. We conclude that protein meal induces glomerular hyperfiltration in renal disease and that this protein-induced hyperfiltration is not mediated by angiotensin II. Because glomerular hyperfiltration is implicated in the progression of renal disease, these data suggest that even in patients who have advanced renal failure, high-protein diets may exert a detrimental effect on the kidney.
 ...
PMID:Preservation of renal reserve in chronic renal disease. 198 65

An attenuation of adrenergic activity during the inhibition of endogenous angiotensin II formation was evaluated by determining plasma norepinephrine concentration after a single oral administration of captopril compared to that after nifedipine in essential hypertension. Captopril produced a fall in mean arterial pressure (-24 +/- 2 mmHg, p less than 0.01) which magnitude was the same as that gained by nifedipine (-22 +/- 3 mmHg, p less than 0.01). Reflex tachycardia due to hypotension was produced (+13 +/- 1 beats/min, p less than 0.01) after nifedipine but not after captopril (-1 +/- 2 beats/min, p greater than 0.05). Although the enhancement of plasma renin activity induced by captopril (+1.54 +/- 0.56 ng/ml/hr, p less than 0.05) was similar (p greater than 0.05) to that by nifedipine (+1.44 +/- 0.47 ng/ml/hr, p less than 0.05), plasma norepinephrine concentration increased less (p less than 0.01) after captopril (+100 +/- 23 ng/ml, p less than 0.05) than after nifedipine (+283 +/- 51 ng/ml, p less than 0.05). Thus, the diminished adrenergic activity is a likely candidate for the abolished reflex tachycardia after the inhibition of angiotensin I converting enzyme activity by captopril in essential hypertension.
 ...
PMID:Captopril attenuates reflex adrenergic response in essential hypertension. 199 80

In confirmation of a previous study, rats of the Dahl S and R sublines exhibited no spontaneous preference for dilute NaCl solutions and an aversion for isotonic and hypertonic NaCl solutions when they were offered in a 2-bottle choice with water. A hysteresis effect was observed when choice was offered between water and a descending series of concentrations of NaCl solution compared with a preceding increasing series. In response to either chronic dietary administration of an angiotensin I converting enzyme inhibitor (ACEI) or acute sodium depletion, rats of the R subline developed a strong NaCl appetite, but the S subline did not. In contrast, rats of both sublines showed an NaCl appetite in response to a regimen of deoxycorticosterone acetate (DOCA). In acute drinking tests, rats of the S subline drank less water than those of the R subline in response to administration of either isoproterenol, ACEIs, or hypovolemia. Both R and S sublines drank similar amounts of water after SC administration of angiotensins I and II, and hypertonic NaCl. Compared with R rats, S rats had lower plasma renin activity in several of the above conditions, and their decreased thirst and sodium appetite appears to be a direct result of an underactive renin-angiotensin system.
 ...
PMID:Thirst and sodium appetite in Dahl rats. 215 63


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>