Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Plasma renin activity (PRA), renin substrate concentration (PRS), aldosterone concentration (PA), and cortisol levels were determined in five camels during dehydration (8-10 days complete denial of water) and at timed intervals after rapid rehydration in cool spring and hot summer weather. Plasma sodium concentration increased from 138 +/- 3.7 to 147 +/- 2.5 (mean +/- SE) meq/l during spring dehydration, and from 146 +/- 1.3 to 157 +/- 1.14 meq/l during dehydration in the summer. Plasma sodium concentration returned to control levels over the course of several hours following rapid rehydration. Only minor changes in plasma potassium concentration occurred. The hormonal changes were accentuated in the summer dehydration. PRA increased slightly on dehydration, and returned to control levels over the course of several hours following rehydration. PA increased slightly on dehydration but was markedly elevated 24 h after rehydration. PRS showed a slight increase following rehydration in the spring experiment, but no significant change in the summer experiment. Changes in cortisol were insignificant. The results are consistent with a role for angiotensin and aldosterone in enhancing sodium and water reabsorption from kidney and large intestine on dehydration in this species.
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PMID:Response of the renin-aldosterone system in the camel to acute dehydration. 67 13

The rate of angiotensin generation with added renin in plasma from patients with benign essential hypertension has been shown to be higher than in plasma from norm ensive controls. An index of the angiotensin generation rate in relation to to al plasma renin substrate (PRS-r index) has been defined which allows for screening for "activated" plasma. In hypertensive subjects, this index was shown to be higher than that of the normotensive subjects (61 plus or minus 2.4 SE, and 45 plus or minus 5 SE). The index did not correlate with the absolute levels of blood pressure, 24-hour sodium excretion, or plasma renin activity in hypertensive subjects either during the control period or during acute alterations of blood pressure, but was shown to respond in a parallel fashion with chronically induced changes in blood pressure and circulating levels of angiotensin I. By the use of an isolated system of human renin and homologous renin substrate, we have demonstrated that plasma from hypertensive subjects contains a modifier of the renin reaction which increases both V-max and Km of the system, behaving as an uncompetitive activator. No significant change was noted with the addition of normal plasma to the same isolated system.
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PMID:A circulating renin activator in essential hypertension. 80 72

In 7 out-patients with Addison's disease, plasma renin activity (PRA), plasma concentrations of angiotensin II (AT II), renin substrate (PRS), potassium, sodium and total protein, hematocrit, blood pressure, heart rate and body weight were studied after 2 weeks each on 2 mg of dexamethasone, 25 mg hydrocortisone (HC), 25 mg HC + 0.05 mg 9-alpha-fluorohydrocortisone (FC), 25 mg HC + 0.1 mg FC and 25 mg HC + 0.2 MG FC. Four further patients were less extensively studied. Mean PRA (upper normal limit, ambulatory: 12 ng AT I-ml-1-h-1) after the 5 steps of incremental substitution, starting with dexamethasone, was 192, 59, 38, 24 and 9 ng AT I-ml-1-h-1 rsp. PRS did not change with increasing substitution. PRA and AT II were significantly correlated (r = 0.91; p less than 0.0001) and proved to be the most sensitive parameters of insufficient mineralocorticoid substitution. With decreasing significance, PRA also correlated with plasma protein concentration, plasma sodium concentration (negative), delta body weight (negative), heart rate, delta mean blood pressure (negative) and plasma potassium concentration. PRA or AT II measurements are useful clinical tools to control mineralocorticoid substitution in Addisonian patients. Inappropriately high substitution can be prevented by keeping PRA in the upper normal range.
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PMID:Control of mineralocorticoid substitution in Addison's disease by plasma renin measurement. 94 Feb 96

In 22 hypertensive patients with unilateral renal artery stenosis (RAS) and in 8 patients with unilateral or bilateral renal or renal arterial disease, plasma renin activity (PRA), renin substrate (PRS), and angiotensin II (AT II) concentrations were measured in both renal veins and in a peripheral vein 1-2 h after stimulation of renin secretion by injection of frusemide. In patients with elevated PRA in venous blood from a kidney with RAS, AT II was either also elevated, lower than or equal to PRA in peripheral blood, while the contralateral kidney almost invariably extracted AT II. In the 8 patients with variable renal diseases, the concordance between PRA and AT II measurements was better. Results suggest that AT II measurements in renal venous blood are less useful in assessing the functional significance of a RAS than those of PRA. Since PRS is not different in venous plasma of the diseased and the normal kidney, PRA measurements can be regarded as proportional to plasma renin concentration in this condition.
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PMID:Renin, renin substrate and angiotensin II concentration in renal venous blood. 102 64

The relationship between plasma renin activity (PRA), angiotensin II (AT II) and renin substrate concentration (PRS) were studied in a patient with left renal artery occlusion and malignant hypertension before and after left-side nephrectomy. Initially, PRA and AT II were grossly elevated, while PRS was low. Treatment with alpha-methyl-DOPA and saline led to a fall in PRA and AT II and a large rise in PRS. The correlation between PRA and AT II (r=0.937; n=9, p less than 0.001) was highly significant. PRA and PRS were negatively correlated before operation (r=-0.78; n=6; p less than 0.05). A comparison of changes in PRS before and after nephrectomy suggests that renin substrate formation was increased when the ischemic kidney was still in situ. Following nephrectomy, PRA and blood pressure fell to normal within 5 hours, while PRS remained unchanged for this period of time. A two-compartmental analysis of the renin disappearance curve after nephrectomy revealed the presence of a fast and slow component with half-lives of 10 and 95 min, respectively.
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PMID:Changes of plasma renin, angiotensin II and renin substrate during reversal of malignant renovascular hypertension. 120 69

The aim of the present work was to study the relationship between sex hormones and plasma renin levels during the oestrous cycle in a Wistar-derived rat strain. Plasma renin activity (PRA) as well as a plasma renin concentration (PRC) were increased during the day of oestrus in rats with controlled 4-day oestrous cycles. This increase in PRA and PRC was not found when rats were ovariectomized on dioestrus day 2 and samples measured on the expected day of oestrus. The increase in PRA and PRC was not found when normal cyclic rats were treated with either tamoxifen or the progesterone receptor blocker RU 38486. Treatment with progesterone at pro-oestrus after ovariectomy on dioestrus day 2 partially increased the PRA and PRC when compared with the values found during the day of oestrus in control rats. The combined treatment of ovariectomized rats on dioestrus day 2 with oestrogen and progesterone restored the normal increase in PRA and PRC values on the expected day of oestrus. We therefore postulate that the sodium diuresis promoted by progesterone may be modulated by the previous peak of oestrogen. However, stimulation of extrarenal sources of renin cannot be excluded nor can an involvement of inactive precursors of renin in the fluctuations of active renin that occur during the oestrous cycle. No important change in plasma renin substrate (PRC) was observed during the oestrous cycle. PRA, PRC and PRS were determined every 4 h during the 4-day oestrous cycle. Our results clearly show a rhythmic variation in PRA and PRC which increases during the day of oestrus with a peak at 06.00 h.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cyclical changes in plasma renin during the oestrous cycle in the rat: synchronized effect of oestrogen and progesterone. 266 56

The present study examined the effects of low dose ACTH administration (0.1 mg/day for 2 days) on plasma renin concentration, (PRC), activity (PRA) and substrate (PRS), cortisol and aldosterone in man. Six healthy male volunteers on a diet calculated to contain 150 mmol Na/day received an infusion of 5% dextrose (6 ml/h) for 24 hours, then ACTH (Synacthen, Ciba-Geigy) was added to the infusion at the rate of 100 micrograms per day, for 48 h. Blood samples were taken four hourly for determination of plasma cortisol, aldosterone, PRC, PRA and PRS. There was a highly significant increase in plasma cortisol and aldosterone concentrations during ACTH infusion compared with dextrose infusion, but no significant increase in active or inactive PRC, PRA or PRS. In a separate study of 15 healthy male volunteers, dexamethasone (1 mg at 2300 h) suppressed plasma cortisol but had no effect on PRC. These results do not support the view that stimulation of aldosterone by ACTH is mediated through the renin angiotensin system.
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PMID:The effects of ACTH on the renin-aldosterone system in normotensive man. 300 Jun 53

Rats were chronically given 0.5 mg/ml Pb in drinking water. This produced blood and renal lead concentrations of approximately 30 micrograms/dl and 20 micrograms/gm, respectively, significant kidney swelling, but not change in body weight or hematocrit. After 6 weeks of Pb treatment and during ingestion of a sodium-free diet, PRA was elevated (controls: same diet, not lead), but there was no change in PRS. After 5 months the PRA was significantly higher in the lead-treated group even on a 1% NaCl diet, but the difference between groups disappeared on an Na-free diet; that is, the renin response to sodium deprivation was blunted. As early as 6 weeks after beginning lead treatment, the treated group manifested reduced ability to decrease Na excretion following removal of NaCl from the diet; steady-state sodium excretion was normal on either the 1% NaCl or Na-free diet. We conclude that changes in the renin angiotensin system and renal sodium handling the kidneys of rats.
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PMID:Chronic effects of lead on renin and renal sodium excretion. 698 33

The angiotensin I converting enzyme inhibitor (ACEI) perindopril (2 mg/kg body weight), the peripheral vasodilator dihydralazine (DHL) (25 mg/kg body weight) or distilled water was given daily from birth to day 14 to neonatal rats. Blood pressure, plasma creatinine, plasma renin activity (PRA), substrate (PRS) and concentration (PRC) and renin content of kidney tissue sections were evaluated on days 14 and 28. By day 14, a high mortality in the ACEI group was observed. ACEI, but not DHL, led to a significant fall (P < 0.01) in blood pressure, 57 +/- 11 versus 89 +/- 25 in the DHL group and 103 +/- 24 mmHg in controls, and to a dramatic increase in plasma creatinine. PRA and PRS were undetectable in ACEI-treated rats; in contrast, PRC and renal staining with anti-renin antibody were significantly increased in ACEI rats. On day 28, the blood pressure was normal in all groups and plasma creatinine returned to the normal range in ACEI rats. PRA, PRS and PRC were not significantly different in the ACEI group and controls. These results suggest that the renin-angiotensin system (RAS) plays a major postnatal role in the neonatal rat. Inhibition of the RAS during the first 2 weeks of life leads to high mortality, severe hypotension, reversible renal failure and a defect in circulating angiotensinogen.
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PMID:Deleterious effects of inhibition of the renin-angiotensin system in neonatal rats. 763 18

Atrial natriuretic peptide (ANP), plasma renin and renin substrate concentrations (PRC and PRS) were measured in 31 preterm infants with idiopathic respiratory distress syndrome. Infants were studied at a mean of 1.4 days; 17 infants were also studied 2 days later. A 6-hour urine collection was made from 13 male infants on the first day of sampling to assess renal function. Both ANP and PRC were elevated and showed wide ranges of values (geometric means of 620 pg/ml and 18.4 ng/ml/h). Plasma ANP was significantly correlated with pH, PaCO2 and base excess. No correlations with parameters of cardiovascular or renal function were found. Plasma ANP rose in 13 of the 17 paired samples. We suggest that the very high ANP concentrations in these babies are a consequence of the pulmonary haemodynamic disturbances which accompany respiratory distress in the newborn.
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PMID:Atrial natriuretic peptide in the preterm newborn. 794 37


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