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

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.

2013 ◽  
Vol 57 (8) ◽  
pp. 636-641 ◽  
Author(s):  
Rafael Barberena Moraes ◽  
Gilberto Friedman ◽  
Marina Verçoza Viana ◽  
Tiago Tonietto ◽  
Henrique Saltz ◽  
...  

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.


1979 ◽  
Vol 237 (2) ◽  
pp. E158 ◽  
Author(s):  
E Natke ◽  
E Kabela

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.


1963 ◽  
Vol 43 (3) ◽  
pp. 419-429 ◽  
Author(s):  
H. Schriefers ◽  
J. M. Bayer ◽  
M. Pittel

ABSTRACT In vitro perfusion experiments were carried out with adrenal glands surgically removed from a patient with Cushing's syndrome (hyperplasia of the adrenal cortex) and a patient with Conn's syndrome (adrenal cortical adenoma). From the perfusates the following steroids were extracted, estimated and identified: cortisol, corticosterone, 11β-hydroxyandrostenedione, cortisone and aldosterone. The secretion capacities of the right Cushing adrenal and of the adrenal gland bearing the adenoma were compared with each other. In both adrenals cortisol was the main secretion product and the secretion rates of aldosterone were lowest and practically equal. The Cushing adrenal differed from the adrenal gland with the adenoma in its higher secretion rate of all investigated steroids except aldosterone, in its higher cortisol/aldosterone ratio and in its response to the administration of ACTH. To this stimulus the aldosterone production of the Cushing adrenal reacted in the same rate as the cortisol release. The adrenal gland with the adenoma of the patient with Conn's syndrome had only a relatively higher aldosterone secretion rate in respect to its lower cortisol production (lower cortisol/aldosterone ratio). The total preparation consisting of the adrenal with the adenoma responded neither to ACTH nor to hypertensin. The missing response of the adrenal cortex not including the tumor to ACTH is explained by the structural change in the sense of the so called regressive transformation (small zona fasciculata with relative large zona glomerulosa and reticularis) which was found in our case. Dehydroepiandrosterone was demonstrable in none of the perfusate extracts even under the condition where the left adrenal of the Cushing patient was perfused with added 17α-hydroxy-pregnenolone.


1992 ◽  
Vol 133 (2) ◽  
pp. 275-282 ◽  
Author(s):  
I. D. Porter ◽  
B. J. Whitehouse ◽  
G. M. Price ◽  
J. P. Hinson ◽  
G. P. Vinson

ABSTRACT The rat adrenal cortex contains quantities of dopamine that are compatible with its function as a neurotransmitter, suggesting that locally released dopamine may act as a neuroregulator within the gland. This possibility has been tested by comparing the effects of dopamine on aldosterone secretion in the perfused adrenal with the effects of stimuli designed to provoke the release of intraglandular dopamine. Infusion of dopamine (0·1–100 μmol/l for 10-min periods) into the isolated perfused rat adrenal gland resulted in a transient, dose-related reduction of aldosterone secretion to a minimum of approximately 50% of the basal value at 1 μmol dopamine/l (ratio of experimental to control measurements, R = 0·53 ± 0·06 (s.e.m.); n = 5). In contrast, dopamine (1–100 μmol/l) had no effect on aldosterone production by dispersed zona glomerulosa cell preparations incubated in vitro. The effects of changes in K+ concentration (3·9–52 mmol/l) on aldosterone secretion in the perfused gland and dispersed cell preparations were also compared. A similar bell-shaped dose–response relationship was seen in both preparations between 6 and 32 mmol K+/l, with a maximum at 8·4 mmol K+/l and a return to control values with 16, 24 or 32 mmol K+/l. However, infusion of media with very high K+ concentrations (42 or 52 mmol K+/l) reduced the secretion of aldosterone by the perfused gland to approximately 50% of the basal value (R = 0·51 ± 0·05, n = 9; R = 0·49± 0·08, n = 9; respectively) but produced no change in aldosterone production by zona glomerulosa cells. Electrical field stimulation (pulse width 1 ms, 1 Hz at 60 V for 5 min) of the perfused gland also resulted in a reduction in aldosterone secretion (R = 0·66 ± 0·66, n = 6). In the presence of 1 μmol haloperidol/l, a dopamine antagonist, no effect on aldosterone secretion was seen under control conditions, but the responses to 1 μmol dopamine/l, 52 mmol K+/l and field stimulation were eliminated. The results are consistent with the view that aldosterone secretion by the perfused adrenal gland is subject to an inhibitory dopaminergic control, which may originate from catecholaminergic neurones within the gland itself. Journal of Endocrinology (1992) 133, 275–282


2017 ◽  
Vol 232 (3) ◽  
pp. 525-534 ◽  
Author(s):  
Cherish Chong ◽  
Anis Hamid ◽  
Tham Yao ◽  
Amanda E Garza ◽  
Luminita H Pojoga ◽  
...  

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.


2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Katia Mariniello ◽  
Emanuel Rognoni ◽  
Leonardo Guasti

Abstract The adrenal cortex is a dynamic organ that undergoes self-renewal and remodeling in response to the demand for steroids. In the mouse it is divided into two concentric layers, the outer zona glomerulosa and the inner zona fasciculata (ZF), that secrete aldosterone and corticosterone, respectively. Cell fate mapping studies have shown that the maintenance of the cortex relies on a pool of stem/progenitor cells located in the capsular and subcapsular compartments. Two interconnected cell populations have been identified, subcapsular undifferentiated cells secreting the morphogen Sonic Hedgehog (Shh) and capsular Gli1+ cells, which can transduce the Shh signal (1); both populations are precursors of steroidogenic cells and newly formed cells migrate in a centripetal fashion to repopulate the gland until they reach the juxtamedullary region where they undergo senescence and apoptosis. Moreover, our lab has shown that the Notch atypical ligand Delta-Like homologue 1 (Dlk1) is expressed in partially undifferentiated cells of the subcapsular region in rat (2)and human (3)adrenals, whilst it is mostly expressed in capsular cells in mice (4,5). To investigate whether Dlk1 expressing cells contribute to the zonation of the adrenal cortex we conducted lineage tracing analyses using a tamoxifen inducible Dlk1CreERT2mouse model carrying the R26tdTom reporter. Pregnant dames were injected with tamoxifen at embryonic day (e) 12.5 and pups were culled at postnatal day (p) 10 and p38. Analysis of tdTomato expression showed that 35% (p10) and 24% (p38) of Steroidogenic Factor 1(Sf1)+cortical cells were tdTomato+, revealing that capsular Dlk1+cells are steroidogenic precursors. On the other hand, postnatal tamoxifen injections (p0) showed tdTomato+/Sf1+ cells only in 1-2% in cortical cells after 24-months chase, suggesting that the contribution of Dlk1+cells to adrenocortical self-renewal is limited postnatally.However, the Dlk1+population could be reactivated in the adult mouse treated with dexamethasone and was shown to contribute to the regeneration of the ZF once dexamethasone treatment was ceased. 1. King P, et al. Shh signaling regulates adrenocortical development and identifies progenitors of steroidogenic lineages. Proc Natl Acad Sci(2009) 106:21185-211902. Guasti L, et al. Dlk1 Up-Regulates Gli1 Expression in Male Rat Adrenal Capsule Cells Through the Activation of β1 Integrin and ERK1/2. Endocrinology(2013) 154:4675-46843. Hadjidemetriou I, et al. DLK1/PREF1 marks a novel cell population in the human adrenal cortex. J Steroid Biochem Mol Biol(2019) 193:1054224. Guasti L, Candy Sze WC, McKay T, Grose R, King PJ. FGF signalling through Fgfr2 isoform IIIb regulates adrenal cortex development. Mol Cell Endocrinol(2013) 371:182-1885. Heikkilä M, et al. Wnt-4 Deficiency Alters Mouse Adrenal Cortex Function, Reducing Aldosterone Production. Endocrinology(2002) 143:4358-4365


2002 ◽  
pp. 795-802 ◽  
Author(s):  
F Fallo ◽  
V Pezzi ◽  
L Barzon ◽  
P Mulatero ◽  
F Veglio ◽  
...  

BACKGROUND: The presence and pathophysiological role of CYP11B1 (11beta-hydroxylase) gene in the zona glomerulosa of human adrenal cortex is still controversial. METHODS: In order to specifically quantify CYP11B1, CYP11B2 (aldosterone synthase) and CYP17(17alpha-hydroxylase) mRNA levels, we developed a real-time RT-PCR assay and examined the expression in a series of adrenal tIssues, including six normal adrenals from patients adrenalectomized for renal cancer and twelve aldosterone-producing adenomas (APA) from patients with primary aldosteronism. RESULTS: CYP11B1 mRNA levels were clearly detected in normal adrenals, which comprised both zona glomerulosa and fasciculata/reticularis cells, but were also measured at a lower range (P<0.05) in APA. The levels of CYP11B2 mRNA were lower (P<0.005) in normal adrenals than in APA. CYP17 mRNAlevels were similar in normal adrenals and in APA. In patients with APA, CYP11B2 and CYP11B1 mRNA levels were not correlated either with basal aldosterone or with the change from basal aldosterone in response to posture or to dexamethasone. No correlation between CYP11B1 mRNA or CYP11B2 mRNA and the percentage of zona fasciculata-like cells was observed in APA. CONCLUSIONS: Real-time RT-PCR can be reliably used to quantify CYP11B1 and CYP11B2 mRNA levels in adrenal tIssues. Expression of CYP11B1 in hyperfunctioning zona glomerulosa suggests an additional formation of corticosterone via 11beta-hydroxylase, providing further substrate for aldosterone biosynthesis. CYP11B1 and CYP11B2 mRNA levels in APA are not related to the in vivo secretory activity of glomerulosa cells, where post-transcriptional factors might ultimately regulate aldosterone production.


2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Koshiro Nishimoto ◽  
Tsugio Seki ◽  
Yuichiro Hayashi ◽  
Shuji Mikami ◽  
Ghaith Al-Eyd ◽  
...  

Background. The immunohistochemical detection of aldosterone synthase (CYP11B2) and steroid 11β-hydroxylase (CYP11B1) has enabled the identification of aldosterone-producing cell clusters (APCCs) in the subcapsular portion of the human adult adrenal cortex. We hypothesized that adrenals have layered zonation in early postnatal stages and are remodeled to possess APCCs over time.Purposes. To investigate changes in human adrenocortical zonation with age.Methods. We retrospectively analyzed adrenal tissues prepared from 33 autopsied patients aged between 0 and 50 years. They were immunostained for CYP11B2 and CYP11B1. The percentage of APCC areas over the whole adrenal area (AA/WAA, %) and the number of APCCs (NOA, APCCs/mm2) were calculated by four examiners. Average values were used in statistical analyses.Results. Adrenals under 11 years old had layered zona glomerulosa (ZG) and zona fasciculata (ZF) without apparent APCCs. Some adrenals had an unstained (CYP11B2/CYP11B1-negative) layer between ZG and ZF, resembling the rat undifferentiated cell zone. Average AA/WAA and NOA correlated with age, suggesting that APCC development is associated with aging. Possible APCC-to-APA transitional lesions were incidentally identified in two adult adrenals.Conclusions. The adrenal cortex with layered zonation remodels to possess APCCs over time. APCC generation may be associated with hypertension in adults.


1975 ◽  
Vol 80 (1) ◽  
pp. 114-125 ◽  
Author(s):  
Katalin Sz. Szalay ◽  
Ernö Bácsy ◽  
Ervin Stark

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.


Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Eric J Belin de Chantemèle ◽  
Miriam Cortez-Cooper ◽  
Joseph Cannon ◽  
Anne-Cécile Huby

Obesity causes hypertension (HTN) in males and females. While leptin contributes to obesity-induced HTN by increasing sympathetic activity, in males, it is unknown whether similar mechanisms trigger HTN in obese females. Females secrete 3 to 4 times more leptin than males, but do not exhibit high sympathetic tone with obesity. They however show inappropriately high aldosterone levels that positively correlate with adiposity and blood pressure (BP). Here we hypothesized that leptin induces HTN by increasing aldosterone production in obese females. Hypersensitivity to leptin, in lean mice deficient in protein tyrosine phosphatase 1B (PTP1B) or high leptin levels, in obese Agouti (Ay/a) mice induced HTN (WT: 115±2; KO: 124±2; a/a: 113±1; Ay/a: 128±7mmHg, p<0.05) but did not increase sympathetic control of BP (response to ganglionic blockade). Leptin sensitization and obesity however elevated plasma aldosterone levels and adrenal aldosterone synthase (CYP11B2) expression, in females. Chronic leptin (KO+AA: 115±5; Ay/a+AA: 114±5mmHg) or mineralocorticoid (KO+spiro:111±5; Ay/a+spiro: 121±6mmHg) receptors inhibition restored BP to baseline levels in females PTP1B KO and obese agouti mice. Leptin or leptin receptor deficiency in female ob/ob and db/db mice, abolished obesity-induced increases in adrenal CYP11B2 and plasma aldosterone while chronic leptin infusion in female mice triggered a dose-dependent increase in adrenal CYP11B2 and plasma aldosterone levels. Leptin-mediated aldosterone secretion was independent of changes in plasma angiotensin II, potassium and corticosterone (index of ACTH levels) and preserved in the presence of losartan or α and β-adrenergic receptors antagonists. Stimulation of human adrenocortical cells with leptin dose-dependently increased CYP11B2 expression and aldosterone production. While investigating the interaction between percentage of body fat, leptin and aldosterone levels in young healthy adult Caucasians we reported a positive correlation between adiposity and aldosterone, and between leptin and aldosterone in adult women only. Together these data suggest that leptin directly regulates aldosterone secretion and that leptin induces HTN via aldosterone dependent mechanisms in obese females.


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