ADRENAL POTASSIUM AND SODIUM IN EXPERIMENTAL HYPER- AND HYPOALDOSTERONISM IN THE RAT. DETERMINATION BY ELECTRON PROBE X-RAY MICROANALYSIS

1975 ◽  
Vol 80 (1) ◽  
pp. 114-125 ◽  
Author(s):  
Katalin Sz. Szalay ◽  
Ernö Bácsy ◽  
Ervin Stark
Keyword(s):  
Electron Probe ◽  
Sodium Content ◽  
Zona Glomerulosa ◽  
Potassium Content ◽  
Zona Fasciculata ◽  
Aldosterone Secretion ◽  
X Ray ◽  
Intracellular Potassium

ABSTRACT Potassium and sodium contents in the various adrenal zones were determined in experimental hyper- and hypoaldosteronism in the rat by electron probe X-ray microanalysis. The analysis aimed at revealing intracellular values. There was no change in the potassium content of the zona glomerulosa, zona fasciculata and medulla neither in hyperaldosteronism, induced by Na-deficiency, nor in hypoaldosteronism, elicited by Na-rich diet. The sodium content in the zona glomerulosa and zona fascicularis was increased in the Na-loaded rats, while that of the medulla was not changed. Our data are not consistent with the hypothesis that a change of adrenal intracellular potassium would act as a final stimulus in the regulation of aldosterone secretion.

scholarly journals Aldosterone secretion in patients with septic shock: a prospective study

2013 ◽  
Vol 57 (8) ◽  
pp. 636-641 ◽  
Author(s):  
Rafael Barberena Moraes ◽  
Gilberto Friedman ◽  
Marina Verçoza Viana ◽  
Tiago Tonietto ◽  
Henrique Saltz ◽  
...  
Keyword(s):  
Septic Shock ◽  
Serum Levels ◽  
Zona Glomerulosa ◽  
High Dose ◽  
Zona Fasciculata ◽  
Cortisol Secretion ◽  
Aldosterone Secretion ◽  
Acth Stimulation ◽  
Aldosterone Production ◽  
A Prospective Study

OBJECTIVE: To assess serum levels of the main factors that regulate the activation of the zona glomerulosa and aldosterone production in patients with septic shock, as well as their response to a high-dose (250 µg) adrenocorticotropic hormone (ACTH) stimulation test. SUBJECTS AND METHODS: In 27 patients with septic shock, baseline levels of aldosterone, cortisol, ACTH, renin, sodium, potassium, and lactate were measured, followed by a cortrosyn test. RESULTS: Renin correlated with baseline aldosterone and its variation after cortrosyn stimulation. Baseline cortisol and its variation did not correlate with ACTH. Only three patients had concomitant dysfunction of aldosterone and cortisol secretion. CONCLUSIONS: Activation of the zona glomerulosa and zona fasciculata are independent. Aldosterone secretion is dependent on the integrity of the renin-angiotensin-aldosterone system, whereas cortisol secretion does not appear to depend predominantly on the hypothalamic-pituitary-adrenal axis. These results suggest that activation of the adrenal gland in critically ill patients occurs by multiple mechanisms.

Electrical responses in cat adrenal cortex: possible relation to aldosterone secretion.

1979 ◽  
Vol 237 (2) ◽  
pp. E158 ◽  
Author(s):  
E Natke ◽  
E Kabela
Keyword(s):  
Membrane Potential ◽  
Angiotensin Ii ◽  
Adrenal Cortex ◽  
Adrenal Glands ◽  
Membrane Depolarization ◽  
Zona Glomerulosa ◽  
Membrane Potentials ◽  
Zona Fasciculata ◽  
Aldosterone Secretion ◽  
Stimulus Secretion Coupling

The effects of secretagogues for aldosterone release were studied on the membrane potential of cells in the adrenal cortex of the cat. Adrenal glands were excised, sliced, and continuously superfused. Membrane potentials were recorded from both zona glomerulosa and zona fasciculata-reticularis. Secretagogues, angiotensin II (1 microgram/ml) and 20 mM KCl, were found to depolarize cells rapidly. Ouabain (10(-5) M) also depolarized the membrane potential although the response was sluggish. Samples of the superfusate were collected and analyzed by radioimmunoassay for their aldosterone and cortisol content. Depolarizing concentrations of angiotensin II, KCl, and ouabain seemed to increase aldosterone release. Cortisol output was more variable. Saralasin blocked the effects of angiotensin II on the membrane potential. These experiments suggest that membrane depolarization plays a role in the stimulus-secretion coupling of mineral corticoids.

scholarly journals Adrenal Capillary Endothelial Cells Stimulate Aldosterone Release through a Protein That Is Distinct from Endothelin1

Endocrinology ◽  
1999 ◽  
Vol 140 (10) ◽  
pp. 4411-4418 ◽  
Author(s):  
Lori J. Rosolowsky ◽  
Craig J. Hanke ◽  
William B. Campbell
Keyword(s):  
Endothelial Cells ◽  
Receptor Antagonist ◽  
Gel Filtration ◽  
Zona Glomerulosa ◽  
Maximal Response ◽  
Zona Fasciculata ◽  
Aldosterone Secretion ◽  
Etb Receptor ◽  
Capillary Endothelial Cells

Abstract We tested the possibility that bovine adrenal capillary endothelial cells (ECs) stimulate aldosterone secretion from bovine zona glomerulosa (ZG) cells by the release of a transferable factor. In coincubations of ZG cells and ECs in serum-free medium, aldosterone release was stimulated approximately 17-fold, and the stimulation was related to the concentration of ECs. The maximal stimulation by ECs was 75% of the maximal response to ACTH. In contrast, adrenal pericytes and fibroblasts were without effect. ECs incubated alone without ZG cells did not produce aldosterone. Conditioned medium from ECs (EC-CM), but not adrenal fibroblasts, stimulated aldosterone release approximately 3-fold. The stimulation increased with the concentration of EC-CM and the duration of conditioning time. Steroidogenic activity in EC-CM was abolished by pronase treatment, indicating that the active factor was a protein. However, the activity in EC-CM was distinct from that of endothelin-1 (ET-1), an endothelial peptide that also stimulates aldosterone secretion, as it was not blocked by the ETB receptor antagonist PD-145065, it did not alter[ 125I]ET-1 binding to ZG cells, and its release occurred before the release of ET-1. Neither ECs nor EC-CM stimulated the production of cortisol from zona fasciculata cells. The activity of EC-CM was not blocked by an angiotensin II AT1 receptor antagonist or a bradykinin B2 receptor antagonist. EC-CM stimulated increased intracellular calcium in fura-2-loaded ZG cells, but did not increase the production of cAMP. Using gel filtration, this peptide had an approximate molecular mass of 3000 Da and migrated earlier than ET-1. This study demonstrates that ECs in vitro alter steroidogenesis through the release of a transferable substance and suggests the existence of an endothelium-derived steroidogenic factor that is produced by adrenal capillary ECs. This endothelium-derived steroidogenic factor may function in the adrenal gland as a paracrine regulator of aldosterone secretion.

Age-related impairment of K(+)- and ACTH-stimulated aldosterone secretion by rat adrenal capsules

1993 ◽  
Vol 264 (1) ◽  
pp. E82-E89
Author(s):  
K. J. Radke
Keyword(s):  
Zona Glomerulosa ◽  
Threshold Sensitivity ◽  
Zona Fasciculata ◽  
Aldosterone Secretion ◽  
Cortical Function ◽  
Plasma Aldosterone Concentration ◽  
Fischer 344 ◽  
Age Related ◽  
Adrenal Cortical Function

It has been suggested that the decrease in plasma aldosterone concentration with advancing age is due to a direct effect of aging on adrenal cortical function. In this study, aldosterone secretion by adrenal capsules from male Fischer 344 rats that were 3–5, 11–13, and 19–21 mo of age was evaluated. Adrenal capsules, comprising the capsule, zona glomerulosa, and small portions of the zona fasciculata-reticularis, were perifused in vitro. Basal aldosterone secretion progressively decreased with aging. In response to concentrations of KCl that ranged from 5.0 to 9.0 mM and to adrenocorticotropic hormone (ACTH) that ranged from 10(-11) to 10(-8) M, threshold sensitivity of adrenal capsules to these secretagogues decreased with aging. Moreover, the magnitude of change in K(+)- and ACTH-stimulated aldosterone secretion and maximal aldosterone response of the adrenal capsules to KCl decreased with aging. Thus it is concluded that aging directly affects basal aldosterone secretion by rat adrenal capsules and that there is an age-related impairment of threshold sensitivity and responsiveness of adrenal capsules to the secretagogues, KCl and ACTH.

CORTICOSTERONE, 18-OH-DEOXYCORTICOSTERONE, DEOXYCORTICOSTERONE AND ALDOSTERONE SECRETION IN TISSUE CULTURE OF FOETAL RAT ADRENALS IN THE PRESENCE AND THE ABSENCE OF ACTH

1976 ◽  
Vol 83 (4) ◽  
pp. 781-793 ◽  
Author(s):  
M. Salmenperä ◽  
A. I. Kahri
Keyword(s):  
Tissue Culture ◽  
Cortical Cell ◽  
Secretory Activity ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Gas Liquid Chromatography ◽  
Aldosterone Secretion ◽  
Foetal Rat ◽  
Rat Adrenals ◽  
Differentiation Stage

ABSTRACT A method for simultaneous analysis of the main corticosteroids secreted by the rat adrenal is described. Purification is performed using previously established steps involving dichloromethane extraction, ethanol-cyclohexane partition and Sephadex-LH-20 column chromatography. Deoxycorticosterone and aldosterone are then quantitated with radioimmunoassay and corticosterone and 18-hydroxy-deoxycorticosterone with gas liquid chromatography as their 0-methyloxime-trimethylsilyl ethers. The coefficient of variation of the method for these steroids in concentrations found in the tissue culture of foetal rat adrenals varies between 3.9–10.9% The secretion of these steroids in the tissue culture of foetal rat adrenals is studied. The steroid secretory pattern is correlated with a differentiation stage of the cultures as detected by electron microscopy. The initial secretory activity declines considerably after 15 days of cultivation to a low level. This is the case also with respect to aldosterone although the cortical cell population changed from the mixed population of the differentiated (zona fasciculata-like) and undifferentiated (zona glomerulosa-like) cells to homogenous undifferentiated growth. Addition of ACTH increased deoxycorticosterone secretion rapidly. Corticosterone, 18-hydroxy-deoxycorticosterone and aldosterone secretion was observed only after the differentiation of the cells (especially changes in their mitochondrial compartment) was evident morphologically.

Detection of Na+ and K+ in the Rat Adrenal Cortex with the Electron Microprobe

1977 ◽  
Vol 53 (5) ◽  
pp. 423-430 ◽  
Author(s):  
C. Decorzant ◽  
A. M. Riondel ◽  
M.-J. Philippe ◽  
J. Bertrand ◽  
M. B. Vallotton
Keyword(s):  
Adrenal Cortex ◽  
Electron Microprobe ◽  
Electrolyte Concentration ◽  
Zona Glomerulosa ◽  
Plasma Aldosterone ◽  
Zona Fasciculata ◽  
Aldosterone Secretion ◽  
Dietary Regimen ◽  
High K ◽  
Aldosterone Production

1. In order to demonstrate whether modification of aldosterone secretion is mediated by parallel changes of K+ in the adrenal zona glomerulosa, the total (intracellular + extracellular) Na+ and K+ content of the rat adrenal cortex was determined with the electron microprobe. 2. Groups of rats were submitted to one of the following dietary regimens: standard, low Na+, high K+ or high Na+. 3. Distribution of Na+ and K+ across the zona glomerulosa and zona fasciculata was compared. Standards of known electrolyte concentration were also analysed. 4. The [Na+] was found to be greater in the zona glomerulosa than in the zona fasciculata but K+ was distributed evenly in both zones. This was independent of dietary regimen. 5. Aldosterone production, assessed by plasma aldosterone concentrations, could not be correlated with zona glomerulosa K+ content.

Intracellular Potassium and Steroidogenesis of Isolated Rat Adrenal Cells: Effect of Potassium Ions and Angiotensin II on Purified Zona Glomerulosa Cells

1977 ◽  
Vol 53 (3) ◽  
pp. 289-296 ◽  
Author(s):  
C. M. Mackie ◽  
E. R. Simpson ◽  
M. S. R. Mee ◽  
S. A. S. Tait ◽  
J. F. Tait
Keyword(s):  
Angiotensin Ii ◽  
Potassium Concentration ◽  
Zona Glomerulosa ◽  
Intracellular Water ◽  
Potassium Content ◽  
Percentage Increase ◽  
Intracellular Potassium ◽  
External Potassium ◽  
Glomerulosa Cells ◽  
Intracellular Potassium Concentration

1. A method involving centrifugation through phthalate ester oils is described for the rapid separation of isolated cells from suspending medium. Intracellular potassium concentrations and intracellular water space values for isolated adrenal zona glomerulosa and zona fasciculata cells are given. 2. The effects of angiotensin II and a high external potassium concentration (8·4 mmol/l) on intracellular potassium contents, intracellular water spaces and hence intracellular potassium concentrations of purified glomerulosa cells have been investigated. Corticosterone secretion was also measured. Previously reported results showing a significant increase in potassium content with high external potassium were confirmed. However, angiotensin II slightly, but significantly, decreased potassium content. No significant change in intracellular water space or intracellular potassium concentration was observed with either stimulus. 3. Both stimuli significantly increased corticosterone production. There was no correlation between the percentage increase in potassium content or concentration and the percentage increase in steroid output after stimulation with high external potassium. 4. It is concluded that angiotensin II does not stimulate steroidogenesis in adrenal glomerulosa cells by raising the intracellular potassium concentration. The small, but statistically insignificant, increase caused by high-potassium medium is unlikely to be causally linked to steroidogenesis.

scholarly journals Regulation of aldosterone secretion by mineralocorticoid receptor–mediated signaling

2017 ◽  
Vol 232 (3) ◽  
pp. 525-534 ◽  
Author(s):  
Cherish Chong ◽  
Anis Hamid ◽  
Tham Yao ◽  
Amanda E Garza ◽  
Luminita H Pojoga ◽  
...  
Keyword(s):  
Mineralocorticoid Receptor ◽  
Ex Vivo ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Aldosterone Secretion ◽  
Aldosterone Synthase ◽  
Adrenal Steroidogenesis ◽  
Corticosterone Secretion ◽  
Aldosterone Production ◽  
Male Wistar Rats

We posit the existence of a paracrine/autocrine negative feedback loop, mediated by the mineralocorticoid receptor (MR), regulating aldosterone secretion. To assess this hypothesis, we asked whether altering MR activity in zona glomerulosa (ZG) cells affects aldosterone production. To this end, we studied ex vivo ZG cells isolated from male Wistar rats fed chow containing either high (1.6% Na+ (HS)) or low (0.03% Na+ (LS)) amount of sodium. Western blot analyses demonstrated that MR was present in both the ZG and zona fasciculata/zona reticularis (ZF/ZR/ZR). In ZG cells isolated from rats on LS chow, MR activation by fludrocortisone produced a 20% and 60% reduction in aldosterone secretion basally and in response to angiotensin II (ANGII) stimulation, respectively. Corticosterone secretion was increased in these cells suggesting that aldosterone synthase activity was being reduced by fludrocortisone. In contrast, canrenoic acid, an MR antagonist, enhanced aldosterone production by up to 30% both basally and in response to ANGII. Similar responses were observed in ZG cells from rats fed HS. Modulating glucocorticoid receptor (GR) activity did not alter aldosterone production by ZG cells; however, altering GR activity did modify corticosterone production from ZF/ZR/ZR cells both basally and in response to adrenocorticotropic hormone (ACTH). Additionally, activating the MR in ZF/ZR/ZR cells strikingly reduced corticosterone secretion. In summary, these data support the hypothesis that negative ultra-short feedback loops regulate adrenal steroidogenesis. In the ZG, aldosterone secretion is regulated by the MR, but not the GR, an effect that appears to be secondary to a change in aldosterone synthase activity.

α1H T-type Ca2+ channel is the predominant subtype expressed in bovine and rat zona glomerulosa

2001 ◽  
Vol 280 (2) ◽  
pp. C265-C272 ◽  
Author(s):  
Andrew D. Schrier ◽  
Hongge Wang ◽  
Edmund M. Talley ◽  
Edward Perez-Reyes ◽  
Paula Q. Barrett
Keyword(s):  
Low Voltage ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Mrna Transcript ◽  
Aldosterone Secretion ◽  
Glomerulosa Cells ◽  
Whole Cell Recordings ◽  
Expression Signal ◽  
Zona Glomerulosa Cells

The low voltage-activated (T-type) Ca2+ channel has been implicated in the regulation of aldosterone secretion from the adrenal zona glomerulosa by extracellular K+ levels, angiotensin II, and ACTH. However, the identity of the specific subtype mediating this regulation has not been determined. We utilized in situ hybridization to examine the distribution of three newly cloned members of the T-type Ca2+ channel family, α1G, α1H, and α1I, in the rat and bovine adrenal gland. Substantial expression of only the mRNA transcript for the α1H-subunit was detected in the zona glomerulosa of both rat and bovine. A much weaker expression signal was detected for the α1H transcript in the zona fasciculata of bovine. Whole cell recordings of isolated bovine adrenal zona glomerulosa cells showed the native low voltage-activated current to be inhibited by NiCl2 with an IC50 of 6.4 ± 0.2 μM. Because the α1H subtype exhibits similar NiCl2 sensitivity, we propose that the α1Hsubtype is the predominant T-type Ca2+ channel present in the adrenal zona glomerulosa.

Improvements in the electron probe forming capabilities and x-ray hole counts in the Philips TEM

1983 ◽  
Vol 41 ◽  
pp. 376-377
Author(s):  
Richard L. McConville
Keyword(s):  
Field Strength ◽  
Electron Probe ◽  
Spherical Aberration ◽  
Focal Length ◽  
Objective Lens ◽  
Parallel Beam ◽  
Tilt Axis ◽  
X Ray ◽  
Small Probe ◽  
Specimen Height

A second generation twin lens has been developed. This symmetrical lens with a wider bore, yet superior values of chromatic and spherical aberration for a given focal length, retains both eucentric ± 60° tilt movement and 20°x ray detector take-off angle at 90° to the tilt axis. Adjust able tilt axis height, as well as specimen height, now ensures almost invariant objective lens strengths for both TEM (parallel beam conditions) and STEM or nano probe (focused small probe) modes.These modes are selected through use of an auxiliary lens situ ated above the objective. When this lens is on the specimen is illuminated with a parallel beam of electrons, and when it is off the specimen is illuminated with a focused probe of dimensions governed by the excitation of the condenser 1 lens. Thus TEM/STEM operation is controlled by a lens which is independent of the objective lens field strength.

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