Role of adrenal renin-angiotensin system in the control of aldosterone secretion in sodium-restricted rats

2000 ◽  
Vol 278 (6) ◽  
pp. E1027-E1030 ◽  
Author(s):  
Giuseppina Mazzocchi ◽  
Ludwik K. Malendowicz ◽  
Anna Markowska ◽  
Giovanna Albertin ◽  
Gastone G. Nussdorfer
Keyword(s):  
Enzyme Inhibitor ◽  
Renin Angiotensin System ◽  
Zona Glomerulosa ◽  
Normal Diet ◽  
Angiotensin Ii Receptor ◽  
Aldosterone Secretion ◽  
Angiotensin System ◽  
Renin Angiotensin

This study examined the effect of the pharmacological manipulation of adrenal renin-angiotensin system (RAS) on aldosterone secretion from in situ perfused adrenals of rats kept on a normal diet and sodium restricted for 14 days. Neither the angiotensin-converting enzyme inhibitor captopril nor the nonselective angiotensin II receptor antagonist saralasin and the AT1 receptor-selective antagonist losartan affected basal aldosterone output in normally fed rats. In contrast, they concentration dependently decreased aldosterone secretion in sodium-restricted animals, with maximal effective concentration ranging from 10− 7 to 10− 6 M. Captopril (10− 6 M), saralasin (10− 6 M), and losartan (10− 7 M) counteracted aldosterone response to 10 mM K+ in sodium-restricted rats but not in normally fed animals. Collectively, these findings provide evidence that adrenal RAS plays a role in the regulation of aldosterone secretion, but only under conditions of prolonged stimulation of zona glomerulosa probably leading to overexpression of adrenal RAS.

Involvement of renin-angiotensin system in the reduced pressure natriuresis response of hyperthyroid rats

1995 ◽  
Vol 268 (5) ◽  
pp. E897-E901 ◽  
Author(s):  
J. Garcia-Estan ◽  
N. M. Atucha ◽  
T. Quesada ◽  
F. Vargas
Keyword(s):  
Enzyme Inhibitor ◽  
Renin Angiotensin System ◽  
Renal Perfusion ◽  
Angiotensin Ii Receptor Blocker ◽  
Angiotensin Ii Receptor ◽  
Reduced Pressure ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Pressure Natriuresis

Previous studies have indicated that the pressure diuresis and natriuresis (PDN) response is greatly impaired in thyroxine-treated hypertensive rats. In the present study, we have examined the role of the renin angiotensin system (RAS) as a mediator of these alterations by characterizing the relationships between renal perfusion pressure and urine flow and sodium excretion in hyperthyroid rats acutely treated with a converting-enzyme inhibitor (captopril, 2 mg/kg) or an AT1 angiotensin II receptor blocker (losartan, 10 mg/kg). In the control animals, captopril did not change mean arterial pressure (MAP) or renal blood flow (RBF) but significantly decreased MAP and increased RBF and glomerular filtration rate in the hyperthyroid rats. Captopril did not change the PDN response of the control animals but improved significantly that of the hyperthyroid rats, although it was not completely normalized. Losartan also significantly improved renal hemodynamics and excretion in hyperthyroid rats. These results indicate that an increased intrarenal activity of the RAS is partly responsible for the blunted renal PDN mechanism of the hyperthyroid rats.

Serotoninergic stimulation of aldosterone secretion in the rat in vivo: role of the renin-angiotensin system

1991 ◽  
Vol 130 (3) ◽  
pp. 347-355 ◽  
Author(s):  
E. Davies ◽  
S. Rossiter ◽  
C. R. W. Edwards ◽  
B. C. Williams
Keyword(s):  
Enzyme Inhibitor ◽  
Direct Action ◽  
Renin Angiotensin System ◽  
Aldosterone Secretion ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Corticosterone Secretion ◽  
Sodium And Potassium

ABSTRACT Serotoninergic control of aldosterone secretion in vivo was investigated in conscious rats with indwelling arterial cannulae. Serial blood samples were taken from the animals before and after i.p. administration of 1 ml (4 g/l) 5-hydroxytryptophan (5-HTP), the precursor of serotonin, or saline and they were analysed for 5-HTP, serotonin, 5-hydroxyindoleacetic acid, plasma renin activity (PRA), corticosterone, aldosterone, sodium and potassium concentrations. The role of the renin-angiotensin system was investigated in animals pretreated for 1 week with the angiotensin-converting enzyme inhibitor captopril (25 mg/day). 5-HTP caused a significant increase in all parameters within 45 min except for sodium and potassium. Saline administration showed no significant effect. Captopril pretreatment did not impair the increase in any parameter by 5-HTP, with the exception of the aldosterone response which was significantly attenuated, though not completely. The results show that administration of 5-HTP, which increases serum serotonin levels, stimulates PRA, aldosterone and corticosterone secretion. Captopril pretreatment inhibits the aldosterone response, suggesting that the aldosterone stimulatory properties of 5-HTP require the presence of angiotensin II, although it is unclear whether it acts in a mediatory or permissive capacity. The failure of captopril to inhibit the aldosterone response completely suggests the involvement of other mechanisms such as the hypothalamo-pituitary adrenal axis or a direct action of serotonin on the adrenal. Journal of Endocrinology (1991) 130, 347–355

Role of renin-angiotensin system in glucocorticoid hypertension in rats

1982 ◽  
Vol 243 (1) ◽  
pp. E48-E51 ◽  
Author(s):  
H. Suzuki ◽  
M. Handa ◽  
K. Kondo ◽  
T. Saruta
Keyword(s):  
Blood Pressure ◽  
Intravenous Injection ◽  
Enzyme Inhibitor ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Dependent Manner ◽  
Concurrent Administration ◽  
Angiotensin System ◽  
Renin Angiotensin

The role of the renin-angiotensin system in the regulation of the blood pressure of dexamethasone-treated rats (Dex) was evaluated using saralasin, an angiotensin II antagonist, and SQ 14225 (SQ) (d-3-mercapto-2-methylpropranoyl-1-proline), an angiotensin-converting enzyme inhibitor. During a 7-day period blood pressure rose 65 +/- 10 mmHg (P less than 0.001) in Dex with no significant changes in plasma renin activity. Concurrent administration of dexamethasone and SQ attenuated the elevation of blood pressure (P less than 0.05). In the conscious, freely moving state, intravenous injection of SQ (10, 30, 100 micrograms/kg) reduced blood pressure of DEX in a dose-dependent manner (P less than 0.05). Also, intravenous injection of saralasin (10 micrograms.kg-1 . min-1) reduced blood pressure significantly (P less than 0.01). Bilateral nephrectomy abolished the effects of saralasin and SQ on blood pressure in Dex. These results indicate that the elevation of blood pressure in DEX depends partially on the renin-angiotensin system.

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.

Trophic effects of potassium loading on the rat zona glomerulosa: permissive role of ACTH and angiotensin II

1985 ◽  
Vol 108 (1) ◽  
pp. 98-103 ◽  
Author(s):  
Giuseppina Mazzocchi ◽  
Piera Rebuffat ◽  
Claudia Robba ◽  
Ludwig K. Malendowicz ◽  
Gastone G. Nussdorfer
Keyword(s):  
Angiotensin Ii ◽  
Renin Angiotensin System ◽  
Zona Glomerulosa ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Trophic Effects ◽  
Potassium Loading ◽  
Permissive Role ◽  
Trophic Action

Abstract. The trophic effects of chronic potassium loading on the rat zona glomerulosa were investigated by morphometric and radioimmunological methods. Potassium loading exerted a potent adrenoglomerulotrophic effect in saline treated control rats, but it was not able to reverse the captopril- and dexamethasone-induced atrophy of the zona glomerulosa. However, if the captopril/dexamethasone administered rats were given maintenance doses of angiotensin II and ACTH, potassium loading was found to exert a strong trophic action. The hypothesis is advanced that potassium loading requires the integrity of both the renin-angiotensin system and the hypothalamo-hypophyseal axis to exert its powerful direct stimulating effect on the growth and steroidogenic capacity of the rat zona glomerulosa.

ACUTE ENZYME HISTOCHEMICAL CHANGES IN THE ZONA GLOMERULOSA OF THE RAT ADRENAL CORTEX

1968 ◽  
Vol 59 (3) ◽  
pp. 519-528 ◽  
Author(s):  
J. D. Elema ◽  
M. J. Hardonk ◽  
Joh. Koudstaal ◽  
A. Arends
Keyword(s):  
Adrenal Cortex ◽  
Direct Effect ◽  
Renin Angiotensin System ◽  
Zona Glomerulosa ◽  
Bilateral Nephrectomy ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Histochemical Changes ◽  
Total Nephrectomy

ABSTRACT In order to evaluate a possible role of the renin-angiotensin system in enzyme histochemical changes of the rat adrenal cortex seen after acute hyponatraemia, the effect of a preceding total nephrectomy was investigated. By this procedure it was found that the alterations were largely inhibited. The results therefore favour a role of the renin-angiotensin system in these changes. Moreover it was found that bilateral nephrectomy alone also induced an enhanced zona glomerulosa activity which may be due to a direct effect of changes in potassium homoeostasis.

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