Dose-dependent effects of angiotensin II, acetylcholine and vasopressin on the cytosolic concentration of Ca2+ in suspension primary cultures of zona fasciculata/reticularis cells from bovine adrenal cortex

1991 ◽  
Vol 6 (2) ◽  
pp. 197-203 ◽  
Author(s):  
S. W. Walker ◽  
M. W. J. Strachan ◽  
M. Nicol ◽  
B. C. Williams ◽  
I. M. Bird
Keyword(s):  
Angiotensin Ii ◽  
Suspension Culture ◽  
Adrenal Cortex ◽  
Primary Cultures ◽  
Intracellular Concentration ◽  
Zona Fasciculata ◽  
Adrenocortical Cells ◽  
Intracellular Pool ◽  
Intracellular Ca ◽  
Dose Dependent

ABSTRACT The effects of angiotensin II (AII), acetylcholine and vasopressin on the intracellular concentration of Ca2+ have been little studied in adrenocortical cells from the zona fasciculata/reticularis (ZFR). Primary cultures of bovine ZFR cells maintained in suspension culture for 72 h produce cortisol in response to AII (0·1 μm), acetylcholine (0·1 mm) and vasopressin (1 μm). This response is accompanied by a breakdown of membrane phosphoinositides from [3H]inositol-prelabelled cells. Using cells loaded with the Ca2+ indicator fura-2, the intracellular concentration of Ca2+ was measured in response to increasing doses of all three agonists and found to increase in a graded fashion in each case. The basal intracellular concentration of Ca2+ was 75±3 nm (mean±s.e.m., n=52), rising to a maximum 1·82±0·14-fold (n=6) for AII (0·1 μm), 1·35±0·05-fold (n=7) for acetylcholine (0·1 mm) and 1·27±0·10-fold (n=6) for vasopressin (1 μm). In the case of AII and acetylcholine, agonists were added sequentially in medium of normal extracellular Ca2+ concentration (1·2 mm) or in medium in which the Ca2+ concentration was buffered to approximate to the intracellular concentration of Ca2+ (75–100 nm). Evidence was thereby obtained that both AII and acetylcholine mobilize a common intracellular pool of Ca2+. Our findings suggest that these three agonists, all of which stimulate phospholipase C, increase intracellular Ca2+ through a mechanism which depends, at least in part, on the release of Ca2+ from a common intracellular pool.

scholarly journals Differential production of adrenal steroids by purified cells of the human adrenal cortex is relative rather than absolute

2003 ◽  
pp. 139-145 ◽  
Author(s):  
LS Young ◽  
G Murphy ◽  
SN Kelly ◽  
TP Smith ◽  
SK Cunningham ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Adrenal Cortex ◽  
Zona Glomerulosa ◽  
Growth Patterns ◽  
Zona Fasciculata ◽  
Angiotensin Ii Receptor ◽  
Differential Growth ◽  
Adrenocortical Cells ◽  
Hla Dr ◽  
Fraction I

OBJECTIVES: The adrenal cortex produces aldosterone, cortisol and androgens in response to ACTH and angiotensin II. To define the differential response of morphologically distinct cells of the adrenal cortex, we examined the phenotypical and functional characteristics of human adrenocortical cells. RESULTS: Tumour growth factor-beta receptor-1 (TGFbeta-R1) and CYP-11 were found to be expressed predominantly in the zona fasciculata, whereas human leukocyte antigen (HLA-DR) and CYP-17 were localised to the zona reticularis. The angiotensin II receptor, AT-1, was found to be predominantly expressed in the zona glomerulosa. Adrenocortical cells, separated by density, yielded two distinct fractions which displayed differential growth patterns. Lipid-rich cells of fraction I expressed TGFbeta-R1 and produced significantly more cortisol relative to androstenedione than unseparated or fraction II cells, whereas lipid-poor cells of fraction II expressed HLA-DR and produced more androstenedione relative to cortisol in the presence of ACTH. Aldosterone production by fraction II was significantly greater than fraction I or unseparated cells. TGFbeta-R1-positive fasciculata-type cells separated into fraction I and HLA-DR-positive cells consistent with reticularis cells separated into fraction II. Aldosterone-producing cells indicative of glomerulosa cells separated into fraction II. CONCLUSIONS: Our findings are consistent with the concept that all adrenocortical cells are capable of producing a range of steroids, but the relative production of cortisol, androgen and aldosterone differs.

Effects of angiotensin II and ACTH on normal and tumourous human adrenocortical cells

1983 ◽  
Vol 104 (1) ◽  
pp. 103-109 ◽  
Author(s):  
Wolfgang Belmega ◽  
Wolfgang Oelkers ◽  
Lutz Belkien ◽  
Monika Shirpai ◽  
Ulrich Fiedler ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Renin Angiotensin System ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Adrenocortical Adenoma ◽  
Response Curves ◽  
Adrenocortical Cells ◽  
Normal Cells ◽  
Fold Stimulation

Abstract. Isolated adrenocortical cells from 6 patients with a 'normal' zona fasciculata, 4 patients with a 'normal' zona glomerulosa, and tumour cells from 1 adrenocortical adenoma and 1 carcinoma were incubated with and without increasing concentrations of ACTH 1–24 (10−13 m to 10−9 m) or Asp1-Ile5-angiotensin II (10−11 m to 10−7 m). In 4/5 'normal' cases, cortisol was clearly stimulated by 10−13 m ACTH. The maximum of the dose-response curve (5-fold stimulation) was reached at 10−10 m ACTH. Angiotensin II (All) started to stimulate 'normal' cells at 10−11 m with a maximum (2-fold stimulation) at 10−9 m. Aldosterone production by 'normal' cells was less markedly stimulated by ACTH and All, although the threshold doses for both peptides were similar to those of the cortisol response curves. The cells of the adrenocortical adenoma from a patient with Cushing's syndrome produced large amounts of cortisol and small amounts of aldosterone, both steroids being clearly stimulated by ACTH and AII. The adrenocortical carcinoma cells produced small amounts of cortisol and no aldosterone. Cortisol production responded to ACTH, but not to AII. The results suggest that an activated renin-angiotensin system may stimulate the zona fasciculata, since 10−11 m All (= 10 pg AII/ml) is a normal plasma All concentration on an unrestricted diet. Clinical evidence supporting this thesis is reviewed. However, cortisol production itself will rarely be increased by All in vivo, since a downregulation of ACTH would occur.

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.

TREK-1 K+ channels couple angiotensin II receptors to membrane depolarization and aldosterone secretion in bovine adrenal glomerulosa cells

2004 ◽  
Vol 287 (6) ◽  
pp. E1154-E1165 ◽  
Author(s):  
Judith A. Enyeart ◽  
Sanjay J. Danthi ◽  
John J. Enyeart
Keyword(s):  
Membrane Potential ◽  
Angiotensin Ii ◽  
Adrenal Cortex ◽  
Receptor Activation ◽  
Membrane Depolarization ◽  
Resting Membrane Potential ◽  
Zona Fasciculata ◽  
Ang Ii ◽  
Aldosterone Secretion ◽  
Wide Range

Bovine adrenal glomerulosa (AZG) cells were shown to express bTREK-1 background K+ channels that set the resting membrane potential and couple angiotensin II (ANG II) receptor activation to membrane depolarization and aldosterone secretion. Northern blot and in situ hybridization studies demonstrated that bTREK-1 mRNA is uniformly distributed in the bovine adrenal cortex, including zona fasciculata and zona glomerulosa, but is absent from the medulla. TASK-3 mRNA, which codes for the predominant background K+ channel in rat AZG cells, is undetectable in the bovine adrenal cortex. In whole cell voltage clamp recordings, bovine AZG cells express a rapidly inactivating voltage-gated K+ current and a noninactivating background K+ current with properties that collectively identify it as bTREK-1. The outwardly rectifying K+ current was activated by intracellular acidification, ATP, and superfusion of bTREK-1 openers, including arachidonic acid (AA) and cinnamyl 1–3,4-dihydroxy-α-cyanocinnamate (CDC). Bovine chromaffin cells did not express this current. In voltage and current clamp recordings, ANG II (10 nM) selectively inhibited the noninactivating K+ current by 82.1 ± 6.1% and depolarized AZG cells by 31.6 ± 2.3 mV. CDC and AA overwhelmed ANG II-mediated inhibition of bTREK-1 and restored the resting membrane potential to its control value even in the continued presence of ANG II. Vasopressin (50 nM), which also physiologically stimulates aldosterone secretion, inhibited the background K+ current by 73.8 ± 9.4%. In contrast to its potent inhibition of bTREK-1, ANG II failed to alter the T-type Ca2+ current measured over a wide range of test potentials by using pipette solutions of identical nucleotide and Ca2+-buffering compositions. ANG II also failed to alter the voltage dependence of T channel activation under these same conditions. Overall, these results identify bTREK-1 K+ channels as a pivotal control point where ANG II receptor activation is transduced to depolarization-dependent Ca2+ entry and aldosterone secretion.

Selective Hypoaldosteronism: A Study of Steroid Biosynthetic Pathways under Adrenocorticotrophin and Angiotensin II Infusion

1976 ◽  
Vol 51 (s3) ◽  
pp. 335s-337s ◽  
Author(s):  
M. Lebel ◽  
J. H. Grose
Keyword(s):  
Angiotensin Ii ◽  
Zona Glomerulosa ◽  
Plasma Aldosterone ◽  
Zona Fasciculata ◽  
Biosynthetic Pathways ◽  
Normal Functioning ◽  
Probable Consequence ◽  
Plasma Steroids ◽  
Dose Dependent Increase ◽  
Dose Dependent

1. The functional integrity of the adrenal cortex has been tested in a case of selective hypoaldosteronism by adrenocorticotrophin (ACTH) and angiotensin II (AII) infusion. 2. During ACTH infusion a normal functioning zona fasciculata was indicated by the impressive increase of the ACTH-dependent plasma steroids; the aldosterone response was moderate. 3. During AII infusion the plasma aldosterone response was blunted with an unexpected dose-dependent increase in pregnenolone, resulting in abnormal decreasing progesterone/pregnenolone ratios during the infusion, suggesting a slow-down in the conversion of pregnenolone into progesterone. 4. This defect, a probable consequence of chronic renin deficiency on the zona glomerulosa, could be a contributing factor to the hypoaldosteronism.

Calcium Efflux and Steroid Output from Superfused Rat Adrenal Cells: Effects of Potassium, Adrenocorticotropic Hormone, 5-Hydroxytryptamine, Adenosine 3′:5′-Cyclic Monophosphate and Angiotensins II and III

1981 ◽  
Vol 61 (5) ◽  
pp. 541-551 ◽  
Author(s):  
B. C. Williams ◽  
J. G. McDougall ◽  
J. F. Tait ◽  
S. A. S. Tait
Keyword(s):  
Angiotensin Ii ◽  
Cyclic Amp ◽  
Calcium Transport ◽  
Adrenocorticotropic Hormone ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Calcium Efflux ◽  
Cyclic Monophosphate ◽  
45Ca Efflux ◽  
Dose Dependent

1. The efflux of 45Ca from prelabelled dispersed rat adrenal capsular and decapsulated cell preparations was studied with a column superfusion system. Corticosterone and aldosterone outputs were measured by direct and extraction radioimmunoassays. 2. The stimulants potassium, adrenocorticotropic hormone (ACTH), serotonin and adenosine 3′:5′-cyclic monophosphate (cyclic AMP), at concentrations which gave marked increases in steroid output, had no significant effect on the rate of 45Ca efflux from capsular cell preparations (mainly zona glomerulosa). 3. ACTH, at a concentration which stimulated steriodogenesis similarly, did not alter the rate of 45Ca efflux from decapsulated cell preparations (zona fasciculata/reticularis). 4. [Asp1, Val5]Angiotensin II caused dose-dependent increases in the rate of 45Ca efflux from capsular cells which correlated with corresponding increases in steroid output, but had no effect either on 45Ca efflux or corticosterone output in decapsulated cell preparations. [desAsp1,Ile5]Angiotensin II (angiotensin III) caused similar dose-dependent increases in 45Ca efflux from capsular cells, which correlated with its effects on steroidogenesis, but was less potent in both respects than angiotensin II. 5. Lowered extracellular calcium caused a very marked and rapid increase in 45Ca efflux in capsular-cell preparations, which was not significantly modified by raising the extracellular potassium concentration, although stimulation of steriodogenesis was observed. 6. These findings suggest that in zona glomerulosa cells the stimulants potassium, ACTH, serotonin and cyclic AMP are not coupled to changes in calcium transport indicated by alterations in calcium efflux, whereas angiotensins II and III, the only stimulants examined which do not increase cyclic AMP in these cell preparations, appear to act through a calcium-mediated control mechanism. In zona fasciculata/reticularis cell preparations ACTH does not appear to be coupled to such changes in calcium transport.

scholarly journals Adrenocorticotropin/3′,5′-Cyclic AMP-Mediated Transcription of the Scavenger akr1-b7 Gene in Adrenocortical Cells Is Dependent on Three Functionally Distinct Steroidogenic Factor-1-Responsive Elements

Endocrinology ◽  
2004 ◽  
Vol 145 (2) ◽  
pp. 508-518 ◽  
Author(s):  
Pierre Val ◽  
Christelle Aigueperse ◽  
Bruno Ragazzon ◽  
Georges Veyssière ◽  
Anne-Marie Lefrançois-Martinez ◽  
...  
Keyword(s):  
Adrenal Cortex ◽  
Promoter Activity ◽  
Specific Factor ◽  
Zona Fasciculata ◽  
Adrenocortical Cells ◽  
Steroidogenic Factor 1 ◽  
Basal Promoter Activity ◽  
Nuclear Extracts ◽  
Specific Complex ◽  
Drive Gene

Abstract The akr1-b7 gene encodes a scavenger enzyme expressed in steroidogenic glands under pituitary control. In the zona fasciculata of the adrenal cortex where its expression is controlled by ACTH, AKR1-B7 detoxifies isocaproaldehyde produced during the first step of steroidogenesis. Three steroidogenic factor-1 (SF-1)-responsive elements (SFREs) are contained within the −510/+41 promoter region, which was previously demonstrated to drive gene expression in transgenic mice adrenal cortex. All these sequences bind at least SF-1 in Y1 adrenocortical cell nuclear extracts and can be activated by overexpression of this factor in HeLa cells. However, the three SFREs show distinct properties regarding akr1-b7 promoter activity in Y1 cells. Whereas the proximal −102 SFRE supports basal promoter activity, the −458 bona fide SFRE is essential for both basal promoter activity and cAMP responsiveness, although it is unresponsive to cAMP when isolated from its promoter context. This suggests that SF-1 is not a cAMP-responsive factor per se. The neighboring SFRE at −503 is a palindromic sequence that binds monomeric and heteromeric SF-1 as well as an adrenal-specific complex. Using MA-10 Leydig cells and Y1–10r9 mutant cells, we provide evidence that its activity in adrenocortical cells depends on the binding of the adrenal-specific factor, which is required for basal and cAMP-induced promoter activity. Furthermore, the −503 site has intrinsic cAMP-sensing ability in Y1 cells, which is correlated with increased adrenal-specific complex binding. Collectively, our results suggest that cAMP responsiveness of the akr1-b7 promoter is achieved through cooperation between the adrenal-specific factor bound to the −503 site and SF-1 bound to the −458 site.

scholarly journals Telomerase activity in primary cultures of normal adrenocortical cells

2001 ◽  
Vol 170 (3) ◽  
pp. 677-684 ◽  
Author(s):  
T Suwa ◽  
L Yang ◽  
PJ Hornsby
Keyword(s):  
Primary Culture ◽  
Adrenal Cortex ◽  
Cell Cultures ◽  
Primary Cultures ◽  
Telomerase Activity ◽  
Adrenocortical Cell ◽  
Isolated Cells ◽  
Adrenocortical Cells ◽  
Human Telomerase Reverse Transcriptase ◽  
In Cells

Telomerase activity was measured in isolated cells from bovine and human adrenal cortex, in cells in primary culture, in cells in later passages in culture, and in cells genetically modified by expression of hTERT (human telomerase reverse transcriptase). Telomerase activity in freshly isolated bovine adrenocortical cells and in human adrenal cells from donors of various ages (6-79 years) was very low or undetected. However, primary bovine adrenocortical cell cultures were strongly positive for telomerase activity, and primary human adrenocortical cell cultures were weakly positive. Both cell types proliferate in primary culture but proliferation of bovine cells is much more vigorous. When primary bovine cells were subcultured to make successively secondary and tertiary cultures, telomerase activity declined strongly, and was undetected by the third passage. There was only a slight decrease in growth rate over this period. Levels of the telomerase RNA component did not change with passage number when assessed by semi-quantitative competitive RT-PCR. When both bovine and human cells were infected with a retrovirus encoding hTERT, telomerase activity in the cells was very high. We conclude that in the adrenal cortex, as in some other tissues, TERT expression is regulated and upregulation of telomerase activity is associated with rapid proliferation in primary culture. Telomerase activity is not maintained, and introduction of TERT is required for stable telomerase activity and for immortalization.

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