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 long-term effects of angiotensin (ANGII) on arterial pressure regulation appear to be closely linked to volume homeostasis, via the renal-pressure natriuresis mechanism, both in normal humans and in older hypertensives. In response to disturbances such as increased sodium intake, suppression of ANGII and aldosterone formation greatly amplifies the effectiveness of the pressure natriuresis mechanism, thereby preventing large increases in body fluid volumes and minimizing the rise in blood pressure needed to maintain sodium balance. When ANGII levels are inappropriately elevated, the antinatriuretic effects of ANGII cause increased arterial pressure, which then serves to maintain sodium and water balance via the pressure natriuresis mechanism. The primary intrarenal and extrarenal mechanisms by which ANGII controls renal excretion and arterial pressure include: (1) a direct effect of ANGII on tubular sodium transport; (2) a preferential constrictor action of ANGII on efferent arterioles, which increases sodium reabsorption by altering peritubular capillary physical forces (efferent arteriolar constriction also prevents excessive decreases in glomerular filtration rate when renal perfusion is compromised, such as in renal artery stenosis); and (3) extrarenal effects of ANGII, including stimulation of aldosterone secretion. Current evidence suggests that the direct effects of ANGII on the kidney are quantitatively more important than indirect effects mediated by aldosterone. In older hypertensives, plasma renin activity and aldosterone concentration are often suppressed, perhaps due to loss of functional nephrons and increased sodium chloride delivery to the macula densa of the remaining nephrons.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The renin-angiotensin system. Normal physiology and changes in older hypertensives. 266 88

Single crystals of glycosylated recombinant human renin have been obtained using the hanging-drop vapor diffusion method with polyethylene glycol and sodium chloride as coprecipitants. The crystals belong to the cubic space group P2(1)3 with a = 143.0 A and contain two molecules of renin in the asymmetric unit. A self-rotation function study using 5.5 A data shows the orientation of a non-crystallographic 2-fold axis relating these two monomers.
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PMID:Preliminary crystallographic study of glycosylated recombinant human renin. 268 30

Factors which determine sodium chloride sensitivity, defined as the difference between the mean blood pressure after 1 week of a low sodium chloride diet (3 g/day) and that after 1 week of a high sodium chloride diet (20 g/day), were studied in 60 inpatients with essential hypertension using a multivariate analysis. The sodium chloride sensitivity was independently correlated with the change in erythrocyte sodium concentration (r = 0.47) and with the change in plasma renin activity (r = 0.29); but it was not related to basal blood pressure, the change in plasma volume of the change in plasma norepinephrine concentration. These data suggest that both intracellular sodium accumulation and inadequate suppression of the renin-angiotensin system may be independently involved in the elevation of blood pressure after sodium chloride loading. We could not find the independent importance of volume retention, hyperadrenergic activity or basal blood pressure in the sodium chloride sensitivity.
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PMID:Factors determining sodium chloride sensitivity of patients with essential hypertension: evaluation by multivariate analysis. 270 19

High dietary intake of linoleic acid lowers arterial pressure, and, in vitro, linoleic acid inhibits the enzymatic activity of renin. The purpose of the present study was 1) to evaluate the effect of intravenous infusion of linoleic acid on blood pressure in normotensive and hypertensive Sprague-Dawley rats and 2) to determine whether the hypotensive response to linoleic acid infusion is caused by inhibition of circulating renin. Blood pressure was decreased (P less than 0.01) by linoleic acid infusion in normotensive sodium chloride-deprived animals and in animals with two-kidney, one-clip hypertension. In contrast, linoleic acid infusion did not affect blood pressure in normotensive rats on a "normal" or high sodium chloride intake, in rats with deoxycorticosterone acetate (DOCA)-salt hypertension, and in anephric rats. In sodium chloride-deprived rats, the reduction of blood pressure by linoleic acid infusion was associated with increased plasma renin activity (P less than 0.05); serum angiotensin-converting enzyme activity was unchanged. The in vitro enzymatic activity of exogenous renin in plasma of anephric rats was not affected by linoleic acid infusion. In two-kidney, one-clip hypertensive animals, pretreatment with indomethacin did not alter the hypotensive response to linoleic acid. Thus, although linoleic acid infusion lowered blood pressure in high renin but not in low renin states, the reduction of blood pressure was not related to inhibition of circulating renin or to alterations of endogenous prostaglandin biosynthesis.
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PMID:Effect of linoleic acid infusion on blood pressure in normotensive and hypertensive rats. 276 41

Changes in plasma levels of Na+, K+-ATPase inhibitors with salt loading were studied in eight patients with essential hypertension. By improving the assay method of Na+, K+-ATPase inhibitors to distinguish ouabain and vanadate, two types of inhibitors were detected in the plasma of patients with essential hypertension: One was ouabainlike and the other was nonouabainlike. The ouabainlike inhibitor was detected at low KCl concentrations (0.1 mM) in the assay buffer, and the nonouabainlike inhibitor was detected at a high KCl concentration (10 mM). By increasing dietary sodium chloride from 2 g/day for 5 days to 20 g/day for 6 days, systolic blood pressure increased significantly from 122 +/- 3.9 to 138 +/- 3.8 mmHg (p less than 0.005), whereas plasma renin activity decreased significantly from 3.9 +/- 0.8 to 0.8 +/- 0.3 ng/ml/hr (p less than 0.002). Under these conditions, the ouabainlike inhibitor increased significantly from 6.2 +/- 3.9% to 30.5 +/- 5.9% inhibition (p less than 0.005), after increasing dietary sodium. Furthermore, plasma level of the ouabainlike inhibitor correlated significantly with both systolic blood pressure (p less than 0.05) and daily urinary sodium excretion (p less than 0.01). In contrast, the plasma nonouabainlike inhibitor did not change with high sodium intake and did not correlate with blood pressure and daily urinary sodium excretion. These findings suggest that a ouabainlike inhibitor is involved in the maintenance of high blood pressure induced by high sodium intake in patients with essential hypertension. The role of the nonouabainlike inhibitor in blood pressure regulation is still unknown.
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PMID:Increase in plasma ouabainlike inhibitor of Na+, K+-ATPase with high sodium intake in patients with essential hypertension. 283 25

Two experiments were performed with Sprague-Dawley rats to study the effects of different inhibitors of angiotensin I converting enzyme (ACE) on water intake and sodium appetite. Subcutaneous administration of low doses of either enalapril (MK421) or ramipril (Hoe498), like captopril, was dipsogenic. Acute administration of ramipril also enhanced the drinking response to peripherally administered angiotensin I (Ang I). Higher doses inhibited the drinking response to Ang I, administered acutely either peripherally or centrally. These data provide behavioral evidence that the nonsulfhydryl inhibitors enalapril and ramipril inhibit brain converting enzyme activity and that they are considerably more potent than captopril. All three of these compounds, administered chronically in food, induced an appetite for sodium chloride (NaCl) solution. Enalapril and ramipril were more potent than captopril. Plasma renin activity was increased by each of these inhibitors, but the magnitude of the increase was not clearly related to the amount of NaCl consumed. The water intake in response to acute administration of either Ang I or isoproterenol was not reliably increased in rats treated chronically with these inhibitors.
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PMID:Comparison of the effects of the dipeptidyl peptidase inhibitors captopril, ramipril, and enalapril on water intake and sodium appetite of Sprague-Dawley rats. 285 Aug 16

Atrial natriuretic factor (ANF) antagonizes vasoconstriction induced by numerous smooth muscle agonists and also lowers blood pressure in intact animals. ANF has particularly marked relaxant effects on angiotensin II-contracted vessels in vitro. Sensitivity to the blood pressure-lowering effect of ANF in vivo appears to be enhanced in renin-dependent models of renovascular hypertension compared with other experimental hypertensive models. The depressor action of low, possibly physiological doses of ANF in two-kidney, one-clip Goldblatt rats is due to a decrease in total peripheral resistance. On the other hand, high doses of ANF can lower cardiac output, particularly in volume-expanded models such as deoxycorticosterone-salt hypertension. ANF markedly inhibits renin secretion in intact animals, probably via increased glomerular filtration rate and load of sodium chloride to the macula densa. This effect is masked when renal perfusion is impaired (e.g., via unilateral renal artery constriction), in which case ANF may stimulate renin secretion slightly. ANF also reduces plasma aldosterone in vivo and inhibits basal and agonist-induced aldosterone release from isolated adrenal cortical cells. This effect appears to be especially marked for angiotensin-induced aldosterone production in vivo and in vitro. These findings indicate that ANF has potentially important interactions with the renin-angiotensin-aldosterone system and suggest a role for ANF in the homeostatic control of blood pressure as well as of extracellular fluid volume.
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PMID:Effects of atrial natriuretic factor on blood pressure and the renin-angiotensin-aldosterone system. 294 Jan 20

Atrial natriuretic factor is postulated to act through atrial stretch receptors as a volume regulatory hormone that stimulates diuresis and natriuresis in response to increased atrial pressure. To characterize the stimuli associated with the release of atrial natriuretic factor in humans, we studied 14 normal subjects, both in the supine position and after 10 minutes in an upright posture, while they were on a regular diet (Day 0) and during 3 days of supplemental sodium chloride intake (8 g/day). Radioimmunoassay of plasma atrial natriuretic factor was performed with rabbit antibody to the human hormone amino acids (102-126). Urinary sodium excretion increased from 111 +/- 13 mEq/day (mean +/- SEM) on Day 0 to 275 +/- 15 mEq/day by the third day (Day 3) of high sodium intake. The level of atrial natriuretic factor in the supine position rose from 17 +/- 4 pg/ml (Day 0) to 76 +/- 13 pg/ml on Day 3 (p less than 0.001) and after 10 minutes in an upright posture on Day 3, the level fell to 32 +/- 10 (p less than 0.005). Plasma concentrations of atrial natriuretic factor correlated positively with spot and 24-hour urinary sodium excretion and weight gain, and correlated negatively with plasma aldosterone and renin activity. We conclude that the response of atrial natriuretic factor to sodium loading and posture change in humans is appropriate for a volume regulatory hormone.
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PMID:Sodium loading and posture modulate human atrial natriuretic factor plasma levels. 294 66

In 2 sibs pseudohypoaldosteronism was diagnosed by measurements of high serum aldosterone and elevated plasma renin activity. During their first week of life the first born girl, phenotypically normal, went through a severe salt-losing crisis with hyponatremia and hyperkalemia. Steroids given because of suspected congenital adrenal hyperplasia had no effect. High parenteral and later oral substitution of sodium normalized the serum electrolytes. The younger brother had milder symptoms. His salt-losing crisis developing during the first week of life was treated immediately with salt substitution. Both children developed normally with high oral sodium chloride supplementation, as regulated by the parents, using daily body weight measurements. Both children frequently suffer salt-losing crises, generally preceded by simple upper respiratory tract infections, which have to be treated in the hospital by infusion with a hyperosmolar sodium chloride solution.
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PMID:[Pseudohypoaldosteronism--renal salt loss syndrome. Therapy and course exemplified by 2 siblings]. 294 88

Plasma levels of immunoreactive alpha human atrial natriuretic peptide (IR-ANP) were measured in nine patients with chronic renal failure before and after removal of 1.3-3.7 litres of fluid by ultrafiltration and again during volume repletion with intravenous sodium chloride solution (150 mmol/l: saline). Baseline levels of IR-ANP were elevated but fell by 22% during ultrafiltration. Saline infusion induced a rapid and steep rise in IR-ANP levels which were 150% of baseline while body weight was still 2% below baseline. Changes in plasma renin, angiotensin II, aldosterone and vasopressin during the study were slight compared with the change in IR-ANP, but noradrenaline levels rose threefold during ultrafiltration. There was a significant positive relationship between arterial pressure and IR-ANP levels before and after ultrafiltration. These results lend support to the suggestion that atrial peptides are of physiological importance, especially in states of chronic fluid overload such as chronic renal failure.
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PMID:Exaggerated responsiveness of immunoreactive atrial natriuretic peptide to saline infusion in chronic renal failure. 294 53


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