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)

Angiotensin II is a peptide normally present in the bloodstream and central nervous system. Exogenous angiotensin induces drinking which is inhibited by saralasin, a specific receptor antagonist. Administration of saralasin does not reduce endogenously stimulated drinking. Angiotensin is dipsogenic after intravenous or intracerebroventricular infusion, raising the possibility of multiple access routes to the brain. Water deprived rats were given saralasin by both routes simultaneously to block the access of endogenous angiotensin to recentors reached from blood and ventricular cerebrospinal fluid (CSF). Water deprivation increased plasma (Na+), hematocrit, vasopressin content and renin activity but saralasin treatment did not reduce water intake after 30 or 60 min. Therefore, blood or CSF-bore angiotensin does not appear to be an absolute requirement for water deprivation drinking behavior.
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PMID:Drinking behavior in water deprived rats after angiotensin receptor blockade. 19 67

The two naturally occurring analogues of angiotensin II (AII), Asp1-Val5-AII and Asp1-Ile5-AII, were equally effective as intracranial dipsogens in the water-replete rat. Renin, synthetic tetradecapeptide renin substrate (SRS) and angiotensin I (AI) also produced copious drinking when injected into the brain, but the naturally occurring renin substrate of rat caused little drinking and was much less effective than SRS. Prior intracranial injection of pepstatin, a competitive antagonist of the renin-angiotensinogen reaction, reduced drinking in response to renin and SRS but not to AI and AII. Renin-, SRS- and AI-induced drinking were inhibited by the converting enzyme inhibitor SQ 20881 injected through the same intracranial cannula in antagonist to agonist ratio of 1000:1, whereas the AII response was enhanced, although not significantly so, and the carbachol response was unaffected. Finally, position 8 aliphatic substituted analogues of AII were competitive antagonists of AII-induced drinking, and also inhibited drinking induced by renin, SRS and AI injected through the same intracranial cannula, but they did not inhibit carbachol-induced drinking. In conclusion, the angiotensin-sensitive receptor for thirst does not accept SRS or AI. It responds best to AII.
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PMID:Petide antagonists of the renin-angiotensin system in the characterisation of receptors for angiotensin-induced drinking. 21 Aug 83

Endocrine activity in patients with essential hypertension was studied by measuring the urinary excretion of catecholamines, prostaglandin E (PGE) and cyclic adenosine monophosphate (cAMP). Simultaneously, plasma renin activity, concentrations of serum sodium, potassium, blood urea nitrogen (BUN) and creatinine were determined. Systolic blood pressure and BUN increased progressively with age until the sixth decade. Urinary excretion of norepinephrine was correlated with the systolic blood pressure. In contrast, plasma renin activity and urinary excretion of PGE decreased progressively with the increase in systolic blood pressure. Although the cause of essential hypertension is not known, it is suggested that hypertension accelerates the aging process in the kidney and thus decreases renal PGE synthesis. This decrease of PGE in turn causes a reduction of plasma renin activity, possibly either by accelerating the retention of sodium and water or by failing to stimulate renin synthesis. A decrease of PGE may also potentiate the vasopressor action of norepinephrine.
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PMID:Changes in hormonal activities relative to the severity of essential hypertension. 21 51

The effect of acute administration of SQ 14,225, a new angiotensin converting enzyme inhibitor, on the drinking response of female rats administered either isoprenaline, angiotensin I, or angiotensin II was studied during 2 h after treatment. Administration of isoprenaline (25 micrograms/kg body wt) was accompanied by a significant increase in water intake when compared with saline-treated controls. Acute administration of a constant dose of isoprenaline (25 micrograms/kg body wt) and increasing doses of SQ 14,225 (5--50 mg/kg) was accompanied by a dose-related, linear decrease in water intake. Acute administration of either angiotensin I or angiotensin II (200 micrograms/kg body wt) was accompanied by a significant increase in water intake. The dipsogenic response to angiotensin II was not affected by acute administration of 35 mg SQ 14,225/kg body wt. However, at the same dose of SQ 14,225, angiotensin I-induced thirst was attenuated. Since isoprenaline-induced and angiotensin I-induced, but not angiotensin II-induced, thirsts are blocked by SQ 14,225, the results suggest that isoprenaline-induced thirst is mediated by way of the renin--angiotensin system.
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PMID:Effect of an angiotensin converting enzyme inhibitor (SQ 14,225) on beta-adrenergic and angiotensin-induced thirsts. 22 56

1. Isoprenaline hydrochloride injected subcutaneously in rats given a choice test of 1.8% NaCl and water, first induced saline intake which started immediately and was almost concluded in 15 min, followed by a copious water intake. When either saline or water were given in a separate test, saline intake surpassed the water intake in the first 15 min.2. The delay of 15, 30 or 60 min after injection of isoprenaline, 100 mug/kg, before drinking was allowed, significantly reduced saline intake but did not modify the amount of water subsequently drunk.3. Isoprenaline caused a sudden drop in arterial blood pressure, the extent and duration depending on the dose. The time of maximum drop 3-4 min after injection coincided with the time the rat drank salt.4. Isoprenaline-induced saline drinking was significantly reduced after bilateral nephrectomy but water intake was unaffected.5. The beta-adrenoceptor blocking agent, propranolol, inhibited isoprenaline-induced NaCl and water intake, while the alpha-adrenoceptor antagonist phenoxybenzamine abolished isoprenaline-induced NaCl intake and enhanced water intake.6. Saralasin acetate (P-113), a competitive inhibitor of angiotensin II, given into the third brain ventricle, prevented the isoprenaline-induced NaCl and water intake as well as angiotensin II-induced drinking. The angiotensin converting enzyme inhibitor SQ-20881 reduced the isoprenaline-induced NaCl and water intake.7. In conclusion, hypotension might be a component of salt drinking evoked by isoprenaline although the dipsogenic action of beta-stimulation is mainly due to endogenous renin-angiotensin activation.
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PMID:Drinking behaviour in rats treated with isoprenaline, angiotensin II or angiotensin antagonists. 23 Nov

The role of renin-angiotensin system has been examined in the maintenance of hypertension in acute and chronic two-kidney (36 weeks) and chronic one-kidney (12 weeks) Goldblatt hypertensive rats using three inhibitors of this system. The inhibitors used were URI-73A, a synthetic analog of lysophosphatidylethanolamine, which inhibits renin both in vivo and in vitro, SQ14,225, a potent converting enzyme inhibitor, and [Sar1, Thr8] angiotensin II, an angiotensin II antagonist. When the inhibitors were administered in acute (high renin) hypertensive rats, they all lowered blood pressure significantly. However, in the chronic (low renin) hypertensive phase, both renin and converting enzyme inhibitors lowered blood pressure, whereas, Sar1, Thr8 failed to lower blood pressure. The renin inhibitor lowered plasma renin activity (PRA), and SQ14,225 and [Sar1, Thr8] Ang II increased PRA. Further studies on water and electrolyte balance with one-kidney model hypertensive and uninephrectomized control rats showed no change in plasma volume. However, there was increased 24-hour urinary output and increased sodium excretion. This study indicates that in chronic renal hypertensive rats, blood pressure reduction is possible by either renin on converting enzyme inhibitor, but not by angiotensin antagonists. Since volume did not change either during the development or reversal of hypertension, volume did not appear to play a major role in the maintenance of hypertension.
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PMID:Role of renin-angiotensin system in chronic renal hypertensive rats. 23 87

The evolution of malignant hypertension was studied under metabolic balance conditions in 11 uninephrectomized rats given deoxycorticosterone acetate and 1% NaCl as drinking water. Changes in sodium and potassium balance were related to changes in blood pressure, plasma renin activity, hematocrit, and kidney histology. After 3-4 weeks of steadily positive sodium balance accompanied by continuously increasing blood pressure up to 185 plus or minus 19 (SE) mm Hg, periods of sodium loss accompanied by evidence of hemoconcentration were observed marking the onset of the malignant phase as defined by the development of fibrinoid necrosis in the kidney. Plasma renin activity remained markedly suppressed both at the fourth week (0.33 plus or minus 0.02 ng/ml hour-1) when the sodium balance was positive and the kidney biopsy negative and at the end of the experiment (0.35 plus or minus 0.36 ng/ml hour-1) when the sodium balance was negative and the kidney histology revealed malignant vasculitis. Infusion of the angiotensin II inhibitor 1-Sar-8-Ala-angiotensin II consistently failed to affect blood pressure, and the kidney tissue norepinephrine level was reduced (0.054 plus or minus 0.01 mug/g) compared with the control level (0.132 plus or minus 0.02 mug/g). We conclude that malignant vasculitis in this model is preceded by hypertension associated with sodium and water retention and is accompanied by negative sodium balance, decreases in body weight, falling blood pressure, and hemoconcentration without demonstrable participation of the renin-angiotensin system or the renal catecholamines.
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PMID:Malignant hypertension resulting from deoxycorticosterone acetate and salt excess: role of renin and sodium in vascular changes. 23 7

Renal artery constriction in the unilaterally nephrectomized, trained dog, with maintained renal arterial hypotension, produces a prompt increase in systemic renin activity and blood pressure. The hypertension normally induced by renal artery stenosis is prevented by prior treatment with the nonapeptide Pyr-Trp-Pro-Arg-Pro-Gln-Ile-Pro-Pro (SQ 20, 881), which blocks conversion of angiotensin I to angiotensin II. Constant intravenous infusion of the inhibitor over several days of renal artery constriction prevents the development of chronic renovascular hypertension. Furthermore, a single injection of the nonapeptide restores blood pressure to normal in the early phase of renovascular hypertension, but becomes progressively less effective as salt and water retention occurs in the chronic stage when plasma renin activity returns to control levels. These data provide strong evidence that the renin-angiotensin system is responsible for the initiation of renovascular hypertension in the one-kidney Goldblatt dog, but that other factors become increasingly important in chronic renovascular hypertension.
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PMID:Inhibition of angiotensin conversion and prevention of renal hypertension. 23 18

Release of arginine vasopressin (AVP) from rat neurohypophysis in in vitro studies is significantly augmented by the addition of angiotensin (A-II), and in in vivo studies in dogs renin and A-II were found to stimulate secretion of AVP. Both these results suggest the existence of a direct relationship between the salt regulating renin-angiotensin-aldosterone system and the water controlling AVP system. To evaluate whether such observations apply also in man a sensitive double antibody radioimmunoassay for AVP was developed [17, 18]. Basal plasma levels of AVP in recumbent humans without salt and fluid restriction at room temperature were 3.4 plus or minus 2.2 pg/ml, and 30 min after the onset of an A-II infusion at a concentration of 3-30 ng/min-kg, a significant increase of AVP was found. Maximum measurements were 2-5 times basal levels which returned to normal within 90 min. During the A-II infusion one also noted a 20 mm Hg rise in blood pressure, accompanied by a significant decrease in plasma renin activity. During the same period serum osmolality and serum sodium concentration did not change. Elevation of blood pressure by norepinephrine was not followed by any detectable change of plasma AVP levels, thus excluding a nonspecific blood pressure effect.
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PMID:Angiotensin stimulated AVP-release in humans. 23 67

Conscious Merino ewes were given an intravenous hypertonic sodium chloride load of 4 mmol.min-1 for 100 min. This resulted in increases in urine flow, sodium and potassium excretion and plasma sodium concentration and osmolality. Urinary vasopressin output and solute-free water reabsorption increased and plasma renin activity declined. Renal plasma flow and glomerular filtration rate (GFR) rose, as did the solute clearance. The change in urinary osmolality was related to the initial urine osmolality such that when the initial urine osmolality was high the urine became more dilute, and vice versa. Tubular sodium reabsorption increased but the fractional reabsorption rate fell. It is suggested that the increase in GFR was at least partly due to the increase in AVP and that the electrolyte loss can be accounted for by the increase in GFR without necessarily involving AVP or other hormonal effects at the tubular level.
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PMID:The effect of intravenous hypertonic saline infusion on renal function and vasopressin excretion in sheep. 25 75


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