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)

The concentrations of plasma cAMP and plasma renin activity were determined in arterial and renal venous plasma in nineteen patients investigated for renin-mediated hypertension. The cAMP measurements were performed in two different situations (1) under basal conditions and (2) after i.v. dihydralazine administration, a potent renin stimulation procedure. Thirteen patients had a lateralization of the renin secretion in the basal state and the administration of dihydralazine caused a further marked renin-secretion. The cAMP concentration was higher in the renal veins draining renin-positive kidneys than in the contralateral renal veins. No significant change was observed between the arterial cAMP concentration and the cAMP concentration in either of the renal veins during dihydralazine-stimulated renin secretion. There was no correlation between the cAMP extraction and the renin secretion of the individual kidneys, but the cAMP extraction correlated with the extraction ratio of PAH. These results show that cAMP values are mainly influenced by the renal function and are not related to the state of renin secretion. Increased cAMP levels in renovascular patients and urameic patients are therefore mainly due to defective elimination of the nucleotide by the kidneys.
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PMID:Cyclic AMP, renal function and dihydralazine-stimulated renin secretion in hypertensive patients. 23 May 70

The effect of acute NH4C1-induced metabolic acidemia on renal electrolyte excretion was examined in nine healthy subjects during steady state water diuresis. Following oral NH4C1, venous pH and bicarbonate concentration declined significantly (p less than 0.01) while inulin and PAH clearances remained unchanged. Mean sodium excretion (UNaV) increased from 142 +/- 16 mueq/min (mean +/- SEM) to 310 +/- 49 mueq/min (p less than 0.01) at 8 hr without change in plasma aldosterone or renin levels. Urine flow remained unchanged while CH2O/(CH2O + CCl) declined significantly, suggesting that acute metabolic acidemia inhibits sodium transport in the distal nephron. Similar results were observed in two subjects with central diabetes insipidus. Three subjects restudied following the ingestion of an equivalent amount of chloride administered as NaCl, failed to demonstrate a significant rise in UNaV. UKV fell acutely from 91 +/- 13 to 45 +/- 5 mueq/min (p less than 0.001) despite an increase in serum potassium concentration. No change in plasma insulin was observed. UCaV rose from 66 +/- 15 to 143 +/- 18 microgram/min and fractional excretion of calcium increased from 0.55 +/- 0.13 to 1.24 +/- 0.21% (p less than 0.001). Total serum calcium fell slightly, but ionized calcium rose from 3.99 +/- 0.05 to 4.30 +/- 0.03 mg/dl (p less than 0.001). No change in nephrogenous cyclic (cAMP) excretion was observed. In conclusion, acute metabolic acidemia in man (1) inhibits sodium reabsorption in the distal nephron independent of changes in plasma aldosterone concentration, filtered chloride load, or volume expansion; (2) inhibits potassium excretion despite a rise in serum potassium concentration; and (3) inhibits tubular calcium reabsorption independetn of changes in parathyroid hormone (as reflected by urinary cAMP).
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PMID:Effect of acute metabolic acidemia on renal electrolyte transport in man. 45 20

The renal effects of an acute extracellular fluid volume expansion (50 ml Ringer/kg body weight/60 min) were studied in aldosterone-treated (100 microgram/kg), anesthetized rabbits with and without pretreatment with either indomethacin (3.0 mg/kg) or diclofenac sodium (3.0 mg/kg), two different inhibitors of renal prostaglandin (PG) biosynthesis. In controls (n = 7), the volume expansion increased urine flow from 1.5 +/- 0.24 to 6.1 +/- 0.5 (S.E.) ml/min/100 g kidney weight and sodium excretion from 0.15 +/- 0.03 to 0.99 +/- 0.10 mmol/min/100 g. PAH and inulin clearance increased by 42 and 58%, respectively, while plasma renin activity and urinary excretion of PGF2 alpha-like immunoreactivity were reduced (P less than 0.05). In animals pretreated with indomethacin (n = 6) or diclofenac sodium (n = 6), the diuresis and the natriuresis following volume expansion were significantly increased about two-fold over controls, whereas PAH and inulin clearance, plasma renin activity and hematocrit did not differ from controls. Both drugs were found to reduce urinary excretion of PGF2 alpha-like immunoreactivity by 75--95% througout the experiment. The results indicate that diclofenac sodium, indomethacin and extracellular volume expansion enhance sodium and water excretion partly by suppression of a PG sensitive reabsorption process in the kidney.
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PMID:Indomethacin and diclofenac sodium increase sodium and water excretion after extracellular volume expansion in the rabbit. 66 9

The effect of papaverine on renal function and renin release was investigated in dogs in vivo and in vitro. Intrarenal arterial infusion of 0.1 mg/kg/min of papaverine for 10 minutes caused a significant rise in renal blood flow, a significant decrease in renal vascular resistance, clearance and extraction ratio of creatinine and PAH and in the amount of filtered sodium, without altering arterial blood pressure. There was a significant increase in sodium excretion and in the excreted percentage of filtered sodium (TRFNa). Renin activity (PRA) of arterial blood and renal venous blood, veno-arterious PRA-difference and renin secretion increased significantly after papaverine infusion. In order to eliminate the effect of hemodynamic changes on renin secretion, the effect of papaverine (10(-5), 10(-4)M) was investigated in vitro in surviving canine kidney cortex slices. Papaverine caused a significant increase in renin release and in tissue cAMP concentration. This supports the assumption that the increase in renin secretion might be due to a direct effect on the juxtaglomerular apparatus, by blocking phosphodiesterase activity and by increasing the renal cAMP level.
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PMID:Effect of papaverine on renin release in dogs in vivo and in vitro. 75 46

The mechanism of action of prazosin hydrochloride, a new antihypertensive agent was studied in 14 patients with essential hypertension. Mean supine blood pressure for the group fell from 148/102 +/- 3/2 (SE) mm Hg at baseline to 139/91 +/- 5/4 after eight weeks of therapy (P less than 0.05). No significant postural hypotension was noted in the patients who responded to therapy. Glomerular filtration rate (endogenous creatinine or inulin clearance) and effective renal plasma flow (PAH clearance) remained unchanged during therapy as did supine and stimulated peripheral plasma renin activity. Cardiac output did not change significantly although plasma volume increased in ten out of 12 patients in whom it was measured (P less than 0.025). Among the patients whose mean blood pressure fell 10 mm Hg or more, peripheral vascular resistance fell significantly (P less than 0.025), and the change in plasma volume was not statistically significant. Among the patients whose mean blood pressure changed less than 10 mm Hg with therapy, there was no significant change in peripheral vascular resistance and plasma volume increased significantly (P less than 0.025). Prazosin hydrochloride appears to be an effective antihypertensive agent which acts by peripheral vasodilatation. It may cause fluid retention. The drug does not appear to affect renal function or renin secretion.
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PMID:Physiologic evaluation of a new antihypertensive agent: prazosin HCl. 83 88

The renal effects of i.v. saline loading equal to 1% body weight (b.wt.) were studied in 2 groups of rats: group I was anesthetized with Amytal (15 mg/100 g b.wt. plus supplementary doses), group II with Inactin (12.5-15.0 mg/100 g b.wt.). In group I the saline load caused an increase in urine flow (+92%), solute excretion (+67%), inulin clearance (CIN) (+24%), PAH clearance (+31%) and absolute proximal reabsorption rate (+27%). Proximal fractional reabsorption and filtration fraction (FF) remained unchanged, while plasma oncotic pressure (COP) decreased by 10%. Plasma renin fell and there was an inverse relationship between renin concentration and proximal reabsorption rate. In group II urine flow and solute excretion increased after saline (+85% and 110%, respectively); CIN and absolute proximal reabsorption rate was lower than in group I and failed to increase after saline. Proximal fractional reabsorption was also lower and decreased after saline. COP as well as renin decreased as in group I, but no relationship between renin concentration and proximal reabsorption rate could be demonstrated. The data indicate that Inactin depresses both resting proximal tubular reabsorptive capacity and the tubular response to a physiological volume expansion. The results are compatible with the hypothesis that the renin-angiotensin system is significantly involved in regulation of proximal tubular function, while they are incompatible with the idea that peritubular COP plays any major role in this adjustment.
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PMID:The effect on total renal and tubular function and plasma renin of a moderate isotonic saline load in rats anesthetized with amytal and inactin. 118 88

Potassium canrenoate was administered intravenously, twice at a 9-hr interval, to 3 apparently healthy male volunteers. No consistent changes in endogenous creatinine or PAH clearances were observed for 6 hr after the initial 200-mg dose of this aldosterone antagonist. The clearance of canrenone (the major gamma-lactone metabolite) exceeded by 70% the simultaneous clearance of creatinine from the second through the sixth hour. The excretion of canrenone amounted to 6.8 mg (3.4%) of the dose during the 6-hr clearance study, but was nearly absent (0.2 mg) during the ensuing 6- to 9-hr period. The cumulative excretion of the glucuronide conjugate of canrenone amounted to 4.6 and 2.8 mg (2.3% and 1.4%) of the dose during these respective periods. A sustained retention of K was observed in 1 subject. Otherwise, as was anticipated in the absence of hyperaldosteronism, urinary electrolyte levels were essentially unchanged. Circulating aldosterone and plasma renin activity levels were essentially unaltered.
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PMID:Renal clearance of canrenoate in normal man. 120 80

We describe our observations concerning differences in two groups of young hypertensive patients according to their renin activities after ACE inhibition. Seventeen of these patients (age 26 +/- 7 years), so far untreated, were investigated prospectively for hormone levels (renin, aldosterone, vasopressin), microalbuminuria, renal haemodynamics (inulin and PAH clearance) and signs of organ damage (echocardiography, fundoscopy). Secondary forms of hypertension were excluded by routine methods, including angiography. We differentiated two groups of young hypertensive patients. Group 1 (n = 9) had a false positive captopril test with elevated renin activities after ACE inhibition with captopril (8.4 +/- 5 ng/ml per hour) compared to group 2 (renin activity: 2.2 +/- 1.3 ng/ml per hour) or an increase of greater than 400% of renin activity after ACE inhibition. Baseline renin activities and sodium excretion did not differ between the groups. Group 1 also showed significantly greater GFR, FF, and microalbuminuria, as well as signs of organ damage, with left ventricular hypertrophy and hypertensive changes in fundoscopy. There were no differences between the groups concerning mean arterial blood pressure and duration of hypertension. In conclusion, we were able to demonstrate that patients with highly stimulated renin activities showed signs of visceral organ damage and renal hyperfiltration compared to the normal renin activity group after ACE inhibition. Investigations of the renin-angiotensin-aldosterone system with ACE inhibitors might constitute a helpful indicator of renal changes and organ damages in young hypertensive patients.
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PMID:Renal haemodynamics and organ damage in young hypertensive patients with different plasma renin activities after ACE inhibition. 131 92

Long-term administration of ciclosporin has been complicated by side-effects, the predominant being nephrotoxicity. We performed renal function studies on 20 patients treated with ciclosporin (group 1) and on 12 patients serving as controls (group 2). Only patients with serum creatinine less than 1.3 mg/dl entered the study. The renal function studies consisted of: Inulin clearance, PAH clearance, sodium sulphate loading, sodium bicarbonate loading. Plasma renin activity (PRA), inactive renin (IR) and aldosterone (ALDO) were measured basally and after stimulation with 40 mg furosemide i.v. Serum creatinine was not significantly impaired under ciclosporin with 1.1 +/- 0.1 mg/dl vs 0.9 +/- 0.1 mg/dl in the control group (ns). Glomerular filtration rates as measured by creatinine and inulin clearance were significantly impaired in group 1 as compared to group 2. Inulin clearance was impaired by ciclosporin with 93.5 +/- 4.4 ml/min/1.73 m2 as compared to 121 +/- 6.6 ml/min/1.73 m2 (p less than 0.05) in patients of group 2. The PAH clearance in ciclosporin treated patients was impaired, with 379 +/- 22.1 ml/min/1.73 m2 in group 1 as compared to 605 +/- 39 ml/min/1.73 m2 (p less than 0.001) in group 2. Mean arterial pressure and renovascular resistance were significantly increased in ciclosporin treated patients. We demonstrated, by means of sodium sulphate and bicarbonate loading, incomplete distal tubular acidosis in 3 patients from group 1 but in none of group 2. There was no difference in basal plasma renin activity (PRA), but during volume contraction induced by furosemide there was only blunted response by PRA in patients receiving ciclosporin with 2.7 +/- 0.3 ng/ml/h as compared to 7.7 +/- 0.5 ng/ml/h in controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Kidney function of patients with healthy kidneys during cyclosporin treatment]. 181 17

Arterial hypertension is found in as many as 75% patients with autosomal dominant polycystic kidneys with normal renal function, its pathogenesis is however not quite clear so far. The authors examined 16 patients with polycystic kidneys with normal or only slightly reduced renal function (plasma creatinine lower than 140 umol/l), 8 of these patients were normotonic (N) and 8 hypertonic (H). In all examined subjects right-sided cardiac catheterization was performed with assessment of the minute cardiac volume by thermodilution. To all patients in the course of one hour 1500 ml saline per 70 kg body weight were administered and the haemodynamic examinations were repeated after termination of the infusion. In all subjects before and after expansion the plasma renin activity was assessed (PRA), as well as plasma aldosterone (PA), plasma catecholamines (PC) and the atrial natriuretic factor (ANF), the renal blood flow and glomerular filtration by means of clearance and extraction of PAH and inulin clearance. The authors did not find differences in plasma concentrations, cardiac output and splanchnic and renal ANF extraction in groups N and H, nor in PRA, PA and PC. Volume expansion led in both groups to a comparable rise of ANF and suppression of PRA and PA. Group H did not differ from group N in any of the investigated haemodynamic and renal parameters except for systemic vascular resistance. In hypertensive patients before expansion a close correlation was found between pressure in the pulmonary artery in a wedged position and diuresis (r = 0.935, p less than 0.01) and natriuresis (r = 0.895, p less than 0.01). The volume expansion was in both groups associated with a comparable rise of diuresis, the haemodynamic response of patients N and H was however quite different. While in patients of group N a decline of the systemic vascular resistance occurred as well as an increase of the minute volume without a change of the renal flow and glomerular filtration, in hypertonic patients the systemic vascular resistance and minute volume did not change but there was a significant rise of the renal flow and glomerular filtration. The relationship of diuresis and natriuresis of hypertensive patients with polycystic kidneys to volume parameters and the rise of the renal perfusion pressure during volume expansion indicates the importance of pressure natriuresis for ensuring the sodium and volume homeostasis in these patients.
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PMID:[Hypertension in patients with polycystic kidneys--the effect of volume expansion]. 182 66


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