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)

Previous studies have shown the effects of atrial natriuretic factor (ANF) on rats with renovascular hypertension (RVH). In the present study low dose alpha-hANF (0.025 microgram/kg/min) was administered intravenously for 60 minutes to seven RVH patients. Results demonstrated an inhibition of renin-angiotensin-aldosterone system (RAAS), reduction of plasma catecholamine and arginine vasopressin(AVP), diuresis and natriuresis, increase of hematocrit and creatinine clearance, and slight decrease of blood pressure. These results showed that most factors involved in the establishment and maintenance of RVH are affected by ANF infusion.
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PMID:Effects of atrial natriuretic factor on patients with renovascular hypertension. 128 75

The IV infusion of pharmacological doses (0.05 microgram.kg-1.min-1) of atrial natriuretic peptide to 16 patients with cirrhosis and ascites induced a significant increase in sodium excretion (65 +/- 23 to 517 +/- 231 mu Eq/min), urine volume (10.7 +/- 2.3 to 15.7 +/- 3.7 mL/min), and glomerular filtration rate (89 +/- 4 to 110 +/- 4 mL/min) in only 5 patients (responders). No significant changes in these parameters (15 +/- 6 to 11 +/- 4 mu Eq/min, 5.5 +/- 1.0 to 4.2 +/- 1.1 mL/min, and 81 +/- 5 to 79 +/- 6 mL/min, respectively) were observed in the remaining patients (nonresponders). Compared with responders, nonresponders had significantly lower baseline sodium excretion (P less than 0.02), urine flow (P less than 0.05), free water clearance (2.5 +/- 0.9 vs. 6.9 +/- 2.1 mL/min; P less than 0.05), and mean arterial pressure (82 +/- 3 vs. 96 +/- 2 mm Hg; P less than 0.01) and significantly higher plasma renin activity (16.3 +/- 4.9 vs. 1.8 +/- 0.2 ng.mL-1.h-1; P less than 0.05) and aldosterone level (99 +/- 24 vs. 13 +/- 2 ng/dL; P less than 0.05). Atrial natriuretic peptide produced a similar reduction of arterial pressure in both groups. To investigate whether the blunted natriuretic response to atrial natriuretic peptide in nonresponders was caused by their lower arterial pressure, atrial natriuretic peptide was infused in 7 of these patients after increasing their arterial pressure to the levels of responders with nonrepinephrine. The increase in arterial pressure (from 81 +/- 5 to 95 +/- 5 mm Hg), which was not associated with significant changes in plasma renin activity and aldosterone concentration, did not reverse the blunted renal response to atrial natriuretic peptide in any of these patients. These results indicate that cirrhotic patients with blunted renal response to atrial natriuretic peptide are characterized by low arterial pressure, marked overactivity of the renin-aldosterone system, and severe sodium and water retention. Correction of hypotension without increasing effective blood volume does not restore renal insensitivity to atrial natriuretic peptide.
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PMID:Renal insensitivity to atrial natriuretic peptide in patients with cirrhosis and ascites. Effect of increasing systemic arterial pressure. 142 99

With RIA/HPLC and immunohistochemistry, the presence of angiotensin(A) and atrial natriuretic factor-like materials (ANF-LMs) was demonstrated in the pericardium of human and rats; the distributions of AII and ANF-LMs were found to be identical; AI was more than AII; renin activity was detected in the pericardium. There were three molecular forms of ANF-LMs in the pericardium. Mesothelial cells were the principal endocrine-secreting cells. AII and ANF-LMs of the pericardium were significantly increased in rheumatic heart disease. There were no correlations between plasma AII, ANF, urine AII, ANF and pericardial AII, ANF (P > 0.05). The data reported showed that the pericardium may have endocrine function under normal and abnormal conditions (heart failure) of the heart, in addition to its known mechanical properties.
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PMID:[A study of immunocompetence of peptide hormones in human pericardium]. 130 98

1. In experimental studies, activation of renal sympathetic nerves attenuates the natriuretic response to atrial natriuretic factor. We therefore investigated the response to low-dose infusion of atrial natriuretic factor in renal transplant recipients. 2. Eight male cyclosporin-treated renal transplant recipients received human-alpha atrial natriuretic factor (1-28) at a dose of 1.2 pmol min-1 kg-1 or placebo for 2 h in a placebo-controlled, randomized, cross-over study. The plasma atrial natriuretic factor concentration rose from 18.5 to 49.2 pmol/l in association with an immediate natriuresis (a rise of 49.1 mumol/min in the first 30 min, P less than 0.05; peaking at a 61% increase from baseline, P less than 0.01), diuresis (from 3.37 to 7.46 ml/min) and a threefold rise in urinary cyclic GMP excretion. 3. In response to infusion of atrial natriuretic factor, the packed cell volume rose by 4.2% (P less than 0.001) and the filtration fraction by 5% (from 22 to 27%, P less than 0.05), but there was no significant change in renal plasma flow, glomerular filtration rate or mean arterial blood pressure. Likewise, the plasma catecholamine concentrations, plasma renin activity and serum erythropoietin concentration remained unchanged. 4. The sensitivity of the renal allograft to plasma atrial natriuretic factor concentrations in the high physiological range suggests a role for endogenous atrial natriuretic factor in the modulation of graft function. Furthermore, the immediate natriuretic response to atrial natriuretic factor in the effectively denervated transplant kidney, in contrast to the delayed response seen in normal subjects, may imply that sympathetic nerves have an inhibitory effect on the renal response to atrial natriuretic factor in normal man.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Renal haemodynamic, hormonal and excretory effects of low-dose atrial natriuretic factor infusion in renal transplant recipients. 131 48

The systemic hemodynamic, hormonal, and renal effects of chronic angiotensin-converting enzyme inhibition (CEI) with captopril and the responses to synthetic atrial natriuretic factor (ANF) infusions in the presence and absence of captopril were examined in normal dogs (n = 6) and in dogs with an arteriovenous (AV) fistula and compensated high-output heart failure (n = 6). This experimental model is characterized by normalization of the circulating renin-angiotensin-aldosterone system (RAAS) and persistent elevations in central filling pressures and plasma ANF. In both normal and AV-fistula dogs, oral captopril for 1 wk at 35 mg.kg-1.day-1 in three divided doses produced progressive reductions in arterial and atrial pressures (P less than 0.05), plasma ANF (P less than 0.05), and aldosterone (P less than 0.05). After 1-2 days of a modest increase in urinary sodium excretion (UNaV) (P less than 0.05), all of the dogs regained and maintained sodium balance during captopril administration. On the 8th day of the captopril regimen, synthetic ANF was infused at 15 and 30 ng.kg-1.min-1 for 75-min periods each. Control infusion experiments were performed in the same animals before captopril administration. The normal dogs exhibited dose-related elevations in UNaV (P less than 0.05) that were not augmented with captopril (P greater than 0.05). In contrast, in the AV-fistula dogs the observed renal unresponsiveness to synthetic ANF in the control experiments was reversed with chronic CEI, and ANF-induced UNaV achieved levels comparable to those obtained in the normal animals.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Captopril enhances renal responsiveness to ANF in dogs with compensated high-output heart failure. 131 53

The original observation by de Bold et al. (1981) of a rapid, massive, and short-lasting diuretic and natriuretic effect following injection of rat atrial extracts into intact rats, led to the identification, isolation and purification of the atrial natriuretic factor (ANF). ANF is stored in atrial myocytes and released into the blood stream by atrial distension. Available data suggest that the mechanism of ANF-induced natriuresis involves either renal hemodynamic effects, such as the increase in glomerular filtration rate and reduction of medullary tonicity, or direct effect on sodium transport in the medullary collecting ducts. ANF induces relaxation of vascular smooth muscle, decreases blood pressure and cardiac output. All these effects displayed by ANF are associated to the an inhibition of aldosterone, renin and vasopressin release. Most of these actions are mediated by specific high affinity receptors, which are coupled to a particulate guanylate cyclase. Although ANF levels are increased in some disorders, such as severe heart failure, hypertension, chronic renal failure, the role of the peptide is uncertain. To better define the potential physiopathological role and the possible therapeutic implications of this new hormonal system in conditions of disturbed body fluid and sodium homeostasis, further experimental and clinical data must be awaited.
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PMID:[The physiopathological aspects of the atrial natriuretic factor]. 131 27

The effects of graded supine ergometry on blood pressure, heart rate, and plasma hormones were studied in 14 hypertensive heart transplant recipients before and after 2 weeks and 6 months of enalapril (20 mg/day) plus furosemide (20-80 mg/day) alone or combined with verapamil (120-360 mg/day). Each time, measurements were obtained at rest and at 25 and 50 W exercise. Antihypertensive therapy normalized blood pressure, while heart rate and the blood pressure response to exercise remained unaltered. Pretreatment resting plasma renin activity and catecholamine levels were normal, while atrial natriuretic factor and cyclic guanosine monophosphate concentrations were elevated. All hormones increased significantly with exercise. During treatment, plasma renin activity increased and atrial natriuretic factor and cyclic guanosine monophosphate levels decreased significantly, with a blunted exercise response; concentration of catecholamines increased significantly, with augmented exercise response. Thus, the chosen regimen allowed effective, lasting BP control in hypertensive transplant patients but was associated with significant changes in plasma hormones. Whereas the rise in plasma renin activity may be attributed to converting enzyme inhibition, the decreases in atrial natriuretic factor and cyclic guanosine monophosphate and increases in catecholamine levels seem to indicate marked changes in resting and particularly exercise hemodynamics during antihypertensive therapy.
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PMID:Effects of graded exercise on blood pressure, heart rate, and plasma hormones in cardiac transplant recipients before and during antihypertensive therapy. 131 21

We have investigated whether binding parameters and subtypes of glomerular, papillary, and vascular atrial natriuretic factor (ANF) receptors differ in rats with moderate high-output heart failure [aortocaval (AC) shunt] from their sham-operated controls. Body weight was lower and relative heart weight was higher in the AC shunt group than in the control group. Plasma renin activity (PRA) was also greater in AC shunt rats. Plasma COOH- and NH2-terminal ANF levels were higher in AC shunt animals than in their control counterparts. Total atrial ANF content was elevated in both the right and left atria of the AC shunt group. Glomerular and papillary ANF receptor density (Bmax) and ANF receptor affinity (Kd) were similar in both AC shunt and control rats. Vascular ANF receptor density and affinity were lower in AC shunt (Bmax = 65 +/- 13 fmol.mg protein; Kd = 467 +/- 52 pM) than in control rats (Bmax = 188 +/- 34 fmol.mg protein; Kd = 278 +/- 11 pM). Irreversible cross-linking of 125I-labeled ANF followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing conditions and radioautography demonstrated that both high- and low-molecular weight receptors were unchanged in glomerular membranes and downregulated in vascular membranes from AC shunt animals. However, guanosine 3',5'-cyclic monophosphate (cGMP) production by the isolated glomeruli of AC shunt rats was lower than that of controls. We conclude that in the presence of elevated plasma ANF levels, glomerular, papillary, and vascular ANF receptors may be regulated differently.
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PMID:Divergent regulation of atrial natriuretic factor receptors in high-output heart failure. 133 15

Glomerular hyperfiltration is thought to play a pivotal role in causing renal damage in essential hypertension. An increase in glomerular filtration rate can be experimentally induced by an acute oral protein load through still unclarified mechanisms, although hormonal factors have been postulated; in already hyperfiltering nephrons, the capacity to further increase glomerular filtration rate upon stimulation with an acute protein load (i.e. renal functional reserve) would conceivably be reduced, even in the presence of apparently normal renal function. The present study aimed at assessing whether renal functional reserve is preserved and/or is affected by different antihypertensive drugs in essential hypertensive patients without signs of renal function impairment; moreover, we tried to highlight changes in the plasma levels of natriuretic and antinatriuretic hormones potentially involved in the modulation of renal hemodynamics under the chosen experimental conditions. Renal hemodynamic parameters, plasma renin activity, aldosterone and atrial natriuretic factor were measured in fourteen essential hypertensives submitted to an acute oral protein load, alone or with a concomitant administration of either nifedipine or enalapril, as compared with a control carbohydrate meal. Glomerula filtration rate and renal plasma flow rose slightly but not significantly following an acute oral protein load as compared with a carbohydrate meal; no changes were noted in plasma atrial natriuretic factor levels, whereas plasma renin activity decreased. When nifedipine was administered together with the protein meal, both glomerular filtration rate and renal plasma flow increased significantly; there were also, parallel increases in plasma renin activity and atrial natriuretic factor. Administration of enalapril was associated with a decrease in both glomerular filtration rate and renal plasma flow; plasma renin activity showed an expected marked rise, whereas the plasma levels of atrial natriuretic factor were only slightly but not significantly reduced and plasma aldosterone fell. In conclusion, our data suggest that in our patients renal functional reserve was blunted. Clear-cut hyperfiltration was brought about by administration of nifedipine together with a protein meal, whereas enalapril completely abolished even the small increase in glomerular filtration rate seen after protein meal alone. The concomitant alterations in plasma renin activity, aldosterone and atrial natriuretic factor seemed to play no major role in the determinism of the observed renal hemodynamic changes.
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PMID:Glomerular hyperfiltration in essential hypertension: hormonal aspects. 134 Jun 61

Intraspinally administered alpha 2-adrenergic agonists are being examined for postoperative analgesia, yet their effects on the hemodynamic response to acute hemorrhage have not been examined. In this study chronically prepared conscious sheep received thoracic intrathecal saline or clonidine 300 micrograms followed in 15 min by rapid removal of 1,000 ml blood. In saline-treated ewes blood pressure was maintained and heart rate steadily increased during hemorrhage of up to 700 ml blood, with further blood removal resulting in rapid decreases in both variables. In contrast, heart rate never increased and blood pressure was maintained only up to 400 ml blood loss in animals receiving intrathecal clonidine. Compared to saline controls, clonidine did not alter blood pressure or heart rate at the end of hemorrhage or during blood pressure restitution during the next hour. Clonidine inhibited the increase in plasma epinephrine at the end of hemorrhage without altering plasma norepinephrine, vasopressin, renin, or atrial natriuretic factor. Intrathecal idazoxan, a specific alpha 2-adrenergic antagonist, reversed clonidine's effect on blood pressure during hemorrhage. Intravenous DG-5128, a poorly lipid-soluble alpha 2-adrenergic antagonist, also reversed clonidine's effect and additionally completely blocked any reduction in blood pressure and heart rate during hemorrhage. These data suggest that intrathecal clonidine interferes with maintenance of blood pressure during hemorrhage, likely because of a spinal sympatholytic effect, but does not affect the ultimate decrease in blood pressure after rapid removal of 1,000 ml blood. This difference in effect during the two phases of hemorrhage can be explained by the relative importance of the sympathetic nervous system in each.
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PMID:Intrathecal clonidine and the response to hemorrhage. 135 38


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