The mechanisms and brain regions subserving the suppression of plasma renin concentration caused by intracerebroventricular (ICV) infusion of angiotensin II were studied in sodium-depleted sheep. Infusion of angiotensin II (3 microg/h for 1 hour) into the lateral ventricle reduced plasma renin from 4.3+/-0.4 to 1.6+/-0.2 pmol angiotensin I/mL per hour at 1 hour after the commencement of infusio...

The purpose of this study is to evaluate the relationship between aldosterone and blood pressure in a total of 220 normotensive and 293 essential hypertensive subjects in 2 genetically distinct populations-blacks and white French Canadians. The 24-hour blood pressure monitoring was performed under standardized conditions after discontinuing antihypertensive medications. Plasma renin activity an...

To establish whether the use of proteinase inhibitors in the routine determination of in vitro plasma renin activity overestimates the potency of renin inhibitors in vivo, we examined the effects of phenylmethylsulfonyl fluoride and 8-hydroxyquinoline sulfate on the binding to plasma proteins and the respective IC50 values (50% inhibiting concentrations) of three renin inhibitors. All three ren...

1. The mechanism of increased renin activity after human plasma had been kept at -5 degrees C for 4 days (cryoactivation) was investigated. 2. The increase in renin activity of human plasma by cryoactivation was closely correlated to the increase obtained by incubation with trypsin (r = 0.88, P less than 0.001, n = 10). 3. An inhibitor of thiol enzyme, N-ethylmaleimide did not inhibit cryoactiv...

The interrelationship between renal hemodynamics and the renin-angiotensinaldosterone system in 28 nonazotemic cirrhotic patients has been studied. Patients were divided into three groups: A) Patients without ascites nor edema; B) Patients with ascites and a relatively high sodium excretion (41.9 ± 12.9 mmol/day); and C) Patients with ascites and very low sodium excretion (4.8 ± 0.6 mmol/day). ...

1. Strains of spontaneously hypertensive and normotensive rats were selected by repeated inbreeding. 2. Brief ether anesthesia was shown to produce a two- to three-fold increase in plasma renin activity in both strains. 3. Plasma renin activity was significantly higher in young spontaneously hypertensive than in normotensive rats of the same age (5-7 weeks). After the ninth week plasma renin ac...

We studied the relative rates of release of active and inactive renin by the kidney in anesthetized pigs. Renin concentration was determined in arterial and renal venous plasma as follows: (1) before and after stimulation of renin release with isoproterenol or furosemide, (2) after suppression of renin release by extracellular fluid volume expansion, and (3) after administration of propranolol ...

1. A renin-like enzyme in aortic tissue of the spontaneously hypertensive rat was found to be a freely dissociable enzyme (saline homogenization) with an affinity for the renin inhibitor pepstatin. At neutral pH values, the enzyme was active in homologous plasma to produce angiotensin I, and therefore distinct from pseudorenin and cathepsin D. The arterial enzyme and semi-purified renal renin c...

1. To assess the relative importance of vascular as opposed to plasma renin, groups of conscious rats received a single intravenous injection of partially purified rat renin 18 h after bilateral nephrectomy. Blood pressure was monitored continuously and plasma and aortic renin concentrations were determined at 1, 3, 6 or 9 h after injection. In separate groups of rats the effect of the competit...

a-Methyldopa significantly lowered mean blood pressure and plasma renin activity in dogs anesthetized with sodium pentobarbital. After unilateral ligation of the right renal vessels and contralateral denervation of the kidney, a-methyldopa significantly lowered mean blood pressure but did not change plasma renin activity. It was concluded that a-methyldopa acutely lowers plasma renin activity v...