The Renin–Angiotensin System in Newborn Dogs

1971 ◽  
Vol 49 (2) ◽  
pp. 134-138 ◽  
Author(s):  
P. Granger ◽  
J. M. Rojo-Ortega ◽  
S. Casado Pérez ◽  
R. Boucher ◽  
J. Genest
Keyword(s):  
Peritoneal Dialysis ◽  
Plasma Renin Activity ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Renin Activity ◽  
Renin Release ◽  
Granular Cells ◽  
Angiotensin System ◽  
Juxtaglomerular Cell ◽  
Detailed Evaluation

A detailed evaluation of the rennin–angiotensin system by concurrent determinations of plasma renin activity, renal renin activity, and juxtaglomerular index in newborn dogs during the first 15 days of extrauterine life is described. Findings show that the plasma renin activity is significantly higher for the first 2 weeks of extrauterine life when compared with the values found in adult dogs, and that the renal renin activity is slightly greater despite a very low juxtaglomerular index with a few granular cells, mostly located in the juxtamedullary cortex. Stimulation (peritoneal dialysis) of renin release resulted in a marked increase in plasma renin activity. The juxtaglomerular index was not modified by the stimulation whereas the renal renin activity decreased slightly. From these results, it is suggested that the formation and secretion of renin is well developed in kidneys of newborn dogs despite the absence of demonstrable juxtaglomerular cell granules.

What Stimulates the Renin—Angiotensin System in Rats with two-Kidney Renal Hypertension?

1983 ◽  
Vol 64 (5) ◽  
pp. 463-470
Author(s):  
Y. Takata ◽  
A. E. Doyle ◽  
M. Veroni ◽  
S. G. Duffy
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Renin Activity ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Contralateral Kidney ◽  
The One ◽  
Renin Content

1. Blood pressure, the hypotensive effect of captopril, plasma renin activity, renal renin content and kidney weight were measured in the two-kidney—one-clip model, the one-kidney—one-clip model and the two-kidney—one-clip model with the ureter of the contralateral kidney ligated in rats. The ureteric ligation was performed to abolish urinary excretion from the contralateral kidney in the two-kidney—one-clip model. 2. The development of hypertension after renal artery constriction was earlier and greater in the one-kidney—one-clip model and the two-kidney—one-clip model with ureter of the contralateral kidney ligated than in the two-kidney—one-clip model. A single oral dose of captopril produced a greater fall in blood pressure in both the two-kidney models than in the one-kidney—one-clip group. 3. Plasma renin activity and renal renin content of the clipped kidney were higher in the two-kidney model rats, whether or not the ureter had been ligated, than in the one-kidney—one-clip model animals, although more than half the rats from the two-kidney model had normal values. There was a significant correlation between plasma renin activity and the response to captopril in all groups, whereas in none of the three groups was the correlation between plasma renin activity and blood pressure significant. 4. The clipped kidney had a higher renin content than did the contralateral kidney, and the weight of the ischaemic kidney was decreased compared with the contralateral kidney whether it was untouched or had its ureter ligated. The weight of the clipped kidney was in the order one-kidney—one-clip model > two-kidney—one-clip model with ureter of the contralateral kidney ligated > two-kidney—one-clip model. 5. It was concluded that the renin-angiotensin system was stimulated to the similar degree in some animals for the two-kidney—one-clip models, whether or not the ureter of the contralateral kidney had been ligated, compared with the one-kidney—one-clip animals. This finding suggests that the contralateral kidney can stimulate renin secretion and synthesis in the clipped kidney independently of Na+ excretion.

Plasma renin activity and forearm blood flow in paraplegic humans

1985 ◽  
Vol 59 (3) ◽  
pp. 924-927 ◽  
Author(s):  
P. R. Freund ◽  
G. L. Brengelmann
Keyword(s):  
Blood Flow ◽  
Plasma Renin Activity ◽  
Forearm Blood Flow ◽  
Control Period ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
The Body ◽  
Renin Activity ◽  
Angiotensin System ◽  
Renin Angiotensin

We recently found that paraplegic humans respond to hyperthermia with subnormal increase in skin blood flow (SkBF), based on measurements of forearm blood flow (FBF). Is this inhibition of SkBF a defect in thermoregulation or a cardiovascular adjustment necessary for blood pressure control? Since high resting plasma renin activity (PRA) is found in unstressed individuals with spinal cord lesions and since PRA increases during hyperthermia in normal humans, we inquired whether the renin-angiotensin system is responsible for the attenuated FBF in hyperthermic resting paraplegics. Five subjects, 28–47 yr, with spinal transections (T1-T10), were heated in water-perfused suits. Blood samples for PRA determinations were collected during a control period and after internal temperature reached approximately 38 degrees C. Some subjects with markedly attenuated FBF had little or no elevation of PRA; those with the best-developed FBF response exhibited the highest PRA. Clearly, circulating angiotensin is not the agent that attenuates SkBF. Rather, increased activity of the renin-angiotensin system may be a favorable adaptation that counters the locally mediated SkBF increase in the lower body and thus allows controlled active vasodilation in the part of the body subject to centrally integrated sympathetic effector outflow.

Dopaminergic Control of Aldosterone Secretion is Independent of the Renin—Angiotensin System in Rats

1980 ◽  
Vol 59 (s6) ◽  
pp. 101s-103s ◽  
Author(s):  
J. R. Sowers ◽  
M. L. Tuck ◽  
J. Barrett ◽  
M. P. Sambhi ◽  
M. S. Golub
Keyword(s):  
Plasma Renin Activity ◽  
Enzyme Inhibitor ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Plasma Aldosterone ◽  
Renin Activity ◽  
Dopamine Antagonist ◽  
Aldosterone Secretion ◽  
Angiotensin System ◽  
Renin Angiotensin

1. In rats, intra-arterial metoclopramide, a dopamine antagonist, resulted in an elevation of plasma aldosterone at 5 min and plasma renin activity at 10 min and peak aldosterone and renin responses at 10 and 30 min respectively. 2. Pre-administration of l-dopa blunted and delayed aldosterone and renin responses to metoclopramide, indicating that metoclopramide-induced plasma aldosterone and plasma renin activity increments are mediated by a direct effect of blockade of dopamine receptors rather than other effects of this drug. 3. Pre-administration of angiotensin converting enzyme inhibitor, captopril (SQ 14 225) and the angiotensin II antagonist, saralasin, as well as bilateral nephrectomy did not significantly affect the aldosterone response to metoclopramide, Thus dopaminergic modulation of aldosterone secretion occurs independently of alterations in the renin-angiotensin system. 4. Modulating effects of dopamine on plasma aldosterone are probably mediated by direct effects as well as by interaction with other factors influencing aldosterone secretion at the adrenal zona glomerulosa.

Urinary Prostaglandin E2 and Kallikrein Excretion in Glucocrticoid Hypertension in Rats

1983 ◽  
Vol 65 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Michiko Handa ◽  
Kazuoki Kondo ◽  
Hiromichi Suzuki ◽  
Takao Saruta
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Prostaglandin E2 ◽  
Urine Volume ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Plasma Aldosterone ◽  
Renin Activity ◽  
Concurrent Administration ◽  
Angiotensin System

1. Oral administration of dexamethasone (about 2.5 × 10-7 mol/day) caused hypertension in rats. The blood pressure rose from 108 ± 6 (mean ± sd) to 156 ± 17 mmHg on the seventh day. The urine volume and urinary excretion of sodium were increased. The plasma renin activity and plasma aldosterone were unchanged. However, the urinary excretions of prostaglandin E2 (UPGE2V) and kallikrein (Ukall.V) were markedly decreased throughout the experiment. 2. With concurrent administration of captopril, the elevation of blood pressure was partially prevented. in this group of rats, the plasma renin activity was elevated and the reductions in UPGE2V and Ukall.V were partially prevented. 3. Based on these results, it is suggested that suppression of the kallikrein—kinin and prostaglandin systems, in addition to involvement of the renin-angiotensin system, is one of the factors contributing to the hypertensive action of dexamethasone.

The Sympathetic Nervous System and the Renin-Angiotensin System in Borderline Hypertension

1981 ◽  
Vol 60 (1) ◽  
pp. 25-31 ◽  
Author(s):  
J. W. Henquet ◽  
T. Kho ◽  
M. Schols ◽  
H. Thijssen ◽  
K. H. Rahn
Keyword(s):  
Plasma Renin Activity ◽  
Plasma Concentrations ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Renin Activity ◽  
Plasma Catecholamine ◽  
Bicycle Ergometry ◽  
Angiotensin System ◽  
Plasma Renin Concentration ◽  
Borderline Hypertension

1. Plasma catecholamine levels as well as plasma renin activity and plasma renin concentration were compared in normotensive volunteers and in subjects with borderline hypertension. All subjects were studied at rest and during bicycle ergometry. 2. The two groups of volunteer subjects did not differ in the plasma concentrations of noradrenaline and adrenaline, both at rest and during physical activity. The same was true for plasma renin activity and plasma renin concentration. Furthermore, urinary excretion of noradrenaline, adrenaline and 4-hydroxy-3-methoxymandelic acid was similar in both groups. 3. The results do not support the assumption that there is increased sympathetic activity in subjects with borderline hypertension.

Plasma Renin Activity in Diabetes Mellitus

1979 ◽  
Vol 56 (3) ◽  
pp. 255-259 ◽  
Author(s):  
A. C. Burden ◽  
H. Thurston
Keyword(s):  
Plasma Renin Activity ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Renin Activity ◽  
Diabetic Patients ◽  
Angiotensin System ◽  
Control Subjects ◽  
Untreated Hypertension ◽  
Age And Sex ◽  
Normotensive Control

1. The plasma renin activity (PRA) was measured in 76 diabetic patients who were attending an outpatients clinic. Of these patients 16 had untreated hypertension and 28 had diabetic complications, which ranged from microaneurysms to renal failure and blindness. 2. Compared with age- and sex-matched normotensive control subjects, both normotensive and hypertensive diabetic patients had significantly higher PRA (P < 0·001). 3. Hypertensive diabetic patients also showed a higher PRA than matched hypertensive control subjects (P < 0·005). There were no significant differences between diabetic patients with hypertension or complications compared with those without these features. 4. Although this elevation of PRA could be due to a change in another component of the renin—angiotensin system, hypersecretion of renin is the most likely explanation.

PLASMA RENIN ACTIVITY AND BLOOD CORTICOSTEROIDS IN THE AUSTRALIAN LUNGFISH NEOCERATODUS FORSTERI

1977 ◽  
Vol 74 (1) ◽  
pp. 137-142 ◽  
Author(s):  
J. R. BLAIR-WEST ◽  
J. P. COGHLAN ◽  
D. A. DENTON ◽  
ANGELA P. GIBSON ◽  
CATHERINE J. ODDIE ◽  
...  
Keyword(s):  
Plasma Renin Activity ◽  
Volume Expansion ◽  
Plasma Osmolality ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Renin Activity ◽  
Angiotensin Receptors ◽  
Negative Finding ◽  
Angiotensin System ◽  
Australian Lungfish

Plasma renin activity (PRA) and blood aldosterone and deoxycorticosterone levels were measured in Australian lungfish. Plasma renin activity was depressed after intravenous infusions of iso-osmotic (0·6%) NaCl but not after hypo-osmotic (0·3%) infusions. The presence of PRA in this fish is consistent with prior reports of renal renin activity in other sarcopterygian fishes. The results of the infusion experiments suggest that a fall in plasma osmolality or electrolyte concentrations may oppose the reduction in renin release in response to volume expansion. Aldosterone and deoxycorticosterone were identified in the blood of Neoceratodus. The concentrations of both appeared higher in females than in males. Infusions of [5-valine]-angiotensin II amide for 2–4 h at rates known to increase blood pressure in this species did not alter blood aldosterone concentrations. This negative finding may suggest that the renin/angiotensin system is not involved in aldosterone regulation in Neoceratodus or that angiotensin receptors involved in regulation of steroidogenesis have a greater specificity for endogenous angiotensin than do vascular receptors.

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