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.

The properties of adrenal zona glomerulosa cells after purification by gravitational sedimentation

1974 ◽  
Vol 185 (1081) ◽  
pp. 375-407 ◽  
Keyword(s):  
Angiotensin Ii ◽  
Cyclic Amp ◽  
Microscopic Examination ◽  
Zona Glomerulosa ◽  
Maximal Response ◽  
Zona Fasciculata ◽  
Gravitational Sedimentation ◽  
Rat Adrenals ◽  
Glomerulosa Cells ◽  
Zona Glomerulosa Cells

The densities of latex spheres and biological cells can be reliably determined from their sedimentation rate in an albumin gradient under unit gravitational force. The densities of zona glomerulosa and fasciculata cells of rat adrenals were found to be 1.072 ± 0.004 and 1.040 ± 0.001 respectively. Purified zona glomerulosa cells of rat adrenals can be prepared by gravitational sedimentation of dispersed cells from capsule strippings of the gland, which originally contain 3 to10% zona fasciculata contamination. Electron and phase microscopic examination of the sedimented glomerulosa cells and their steroidogenic response to ACTH and cyclic AMP indicate that they are reasonably free of contamination from zona fasciculata cells. Electron microscopic examination of the purified glomerulosa cells indicates that most of them are reasonably normal in structure. Their basal production of corticosterone is decreased after sedimentation. However, their maximal response of corticosterone output to serotonin and potassium and their response to all potassium concentrations is not significantly altered, indicating normal function for the cells producing steroids. Their maximal responses to ACTH, valine angiotensin II and cyclic AMP are decreased, but, at the doses used, steroidogenesis by the zona fasciculata contamination in the unfractionated preparation would be stimulated by these substances. Purified zona glomerulosa cells have about the same maximal response of corticosterone output (about twofold) to potassium, valine and isoleucine angiotensin II, serotonin and ACTH. The maximal response of the purified zona glomerulosa cells to cyclic AMP is similar to that elicited by valine and isoleucine angiotensin II, potassium, serotonin or ACTH. This indicates that if these stimuli act by increasing cyclic AMP output, then the maximal response of corticosterone output (about twofold) is defined by the limited response of the biosynthetic pathways to cyclic AMP.

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.

scholarly journals The effects of potassium, 5-hydroxytryptamine, adrenocorticotrophin and angiotensin II on the concentration of adenosine 3′:5′-cyclic monophosphate in suspensions of dispersed rat adrenal zona glomerulosa and zona fasciculata cells

1974 ◽  
Vol 142 (2) ◽  
pp. 391-400 ◽  
Author(s):  
Janet D. M. Albano ◽  
Barry L. Brown ◽  
Roger P. Ekins ◽  
Sylvia A. S. Tait ◽  
James F. Tait
Keyword(s):  
Angiotensin Ii ◽  
Bovine Serum Albumin ◽  
Cyclic Amp ◽  
Adrenal Gland ◽  
Incubation Medium ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Adrenal Cells ◽  
Cyclic Amp Accumulation ◽  
K Concentration

Dispersed rat adrenal cells prepared from both the capsule and the decapsulated gland were used to investigate the effects on cyclic AMP accumulation of known stimuli of steroidogenesis [ACTH (adrenocorticotrophin), angiotensin II, K+ions and 5-hydroxytryptamine]. Since glomerulosa-cell preparations from capsular strippings are normally contaminated with a proportion of fasciculata cells, cells purified by fractionation on a bovine serum albumin gradient were also used. The results showed that: (1) ACTH and angiotensin II stimulated cyclic AMP accumulation in both fractionated and unfractionated zona fasciculata cells; (2) 5-hydroxytryptamine and an increased extracellular K+concentration (from 3.6 to 8.4mm) had no effect on cyclic AMP concentrations in fasciculata cell preparations; (3) the addition of ACTH, angiotensin II, 5-hydroxytryptamine or K+to the incubation medium resulted in increased cyclic AMP concentrations in unpurified zona glomerulosa cell preparations; (4) fractionation and hence the virtual elimination of fasciculata contamination, did not affect the response to 5-hydroxytryptamine and increased K+concentration. However, the responses to ACTH and angiotensin II were markedly lowered but not abolished. These results strongly suggest a link between cyclic AMP production and steroidogenesis in the zone of the adrenal gland that specifically secretes aldosterone. All four agents used stimulated both steroid output and cyclic AMP accumulation. However, at certain doses of 5-hydroxytryptamine, K+and angiotensin II the significant increases in corticosterone output were not accompanied by measurable increases in cyclic AMP accumulation.

LACK OF EFFECT OF ANGIOTENSIN ON LEVELS OF CYCLIC AMP IN ISOLATED ADRENAL ZONA GLOMERULOSA CELLS FROM THE RAT

1981 ◽  
Vol 91 (1) ◽  
pp. 145-154 ◽  
Author(s):  
J. B. G. BELL ◽  
J. F. TAIT ◽  
S. A. S. TAIT ◽  
G. D. BARNES ◽  
B. L. BROWN
Keyword(s):  
Angiotensin Ii ◽  
Bovine Serum Albumin ◽  
Cyclic Amp ◽  
Phosphodiesterase Inhibitor ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Angiotensin Iii ◽  
Independent Mechanism ◽  
Glomerulosa Cells ◽  
Zona Glomerulosa Cells

The effects of pure [Asp1, Val5]- and [Asn1, Val5]-angiotensin II and also [des-Asp1, Ile5]-angiotensin II (angiotensin III) on cyclic AMP and steroid outputs by dispersed rat capsular cells, comprising 95% zona glomerulosa and 5% zona fasciculata cells, have been studied. The results showed that [Asp1, Val5]- and [Asn1, Val5]-angiotensin II, at doses between 2·5 × 10−1 1 and 2 × 10−4 mol/l, which produced typical increases in steroidogenesis, failed to increase output of cyclic AMP. This lack of effect was observed whether the nucleotide was measured by radioimmunoassay or by adrenal binding protein and under the same conditions in which 8·4 mm-K+ consistently increased the output of cyclic AMP. Instead the results showed a small but significant decrease in cyclic AMP output with angiotensin II. Similar results were obtained with incubations for 60 rather than 120 min and with medium containing a concentration of 5 or 40 g bovine serum albumin/l. Although the levels of cyclic AMP were generally higher in the presence of the phosphodiesterase inhibitor, 3-isobutyl-l-methylxanthine, the same decrease relative to basal outputs was observed with angiotensin II which increased steroidogenesis. Angiotensin III also failed to increase output of cyclic AMP at doses (2·5×10−9 to 2·5×10−6 mol/l) which produced increases in steroid output equivalent to those obtained with angiotensin II. These results indicate that angiotensin II and III can act through a cyclic AMP- independent mechanism.

Effects of α-melanocyte-stimulating hormone on the cyclic AMP and phospholipid metabolism of rat adrenocortical cells

1986 ◽  
Vol 110 (3) ◽  
pp. 405-416 ◽  
Author(s):  
P. J. Hyatt ◽  
J. B. G. Bell ◽  
K. Bhatt ◽  
F. W. Chu ◽  
J. F. Tait ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Cyclic Amp ◽  
Phosphatidic Acid ◽  
Inositol Phosphates ◽  
Phospholipid Metabolism ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Additional Increase ◽  
Glomerulosa Cells ◽  
Stimulation Of

ABSTRACT Results on the effects of peptides on the phospholipid metabolism and steroid and cyclic AMP (cAMP) outputs of rat adrenal capsular cells (96% zona glomerulosa, 4% zona fasciculata) were obtained in a series of three batch experiments. Their significance was examined by analysis of variance. Incorporation of [32P] into phosphatidylcholine, phosphatidic acid and phosphatidylinositol was measured. Production of [3H]inositol-1 monophosphate, inositol-1,4 bis-phosphate and inositol-1,4,5 tris-phosphate was estimated after prelabelling with [3H]inositol followed by 1 min incubation with a steroidogenic stimulus. Angiotensin II (0·25 nmol/l to 0·25 μmol/l) highly significantly (P < 0·01) stimulated aldosterone and corticosterone outputs, [32P] incorporation into phosphatidic acid and phosphatidylinositol (but not into phosphatidylcholine) and the production of the three [3H]inositol phosphates. Aldosterone and corticosterone outputs were stimulated by α-MSH (above 0·1 nmol/l). However, incorporation of [32P] was not significantly increased until 10 μmol α-MSH/l but, unlike with angiotensin II, incorporation into phosphatidylcholine was also then stimulated. Also, the production of the inositol phosphates was not increased significantly (P > 0·05) by any dose of α-MSH (10 nmol/l, 1 μmol/l and 0·1 mmol/l) used. Therefore, it can be concluded that α-MSH does not stimulate phospholipase C in rat zona glomerulosa cells. In further experiments, it was also found that there were significant increases in cAMP as well as in steroid outputs above 1 nmol α-MSH/l (highly significant above 10 nmol α-MSH/l). There were plateaux of the outputs of both steroids and cAMP from 0·1 to 1 μmol α-MSH/l. However, there were further increases in steroid and cAMP outputs of the capsular cells at higher doses. Concomitant results on the stimulation of corticosterone output by zona fasciculata–reticularis cells indicate that this additional increase was mostly due to the stimulation of the contaminating zona fasciculata cells. It was also confirmed that α-MSH preferentially stimulates steroidogenesis by the zona glomerulosa. However, under our conditions, α-MSH highly significantly increased the output of cAMP by both zona fasciculata and glomerulosa cells. J. Endocr. (1986) 110, 405–416

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.

Hormonal regulation of calcium transport in thick ascending limb renal tubules

1981 ◽  
Vol 241 (2) ◽  
pp. F171-F174 ◽  
Author(s):  
W. N. Suki ◽  
D. Rouse
Keyword(s):  
Parathyroid Hormone ◽  
Cyclic Amp ◽  
Hormonal Regulation ◽  
Calcium Transport ◽  
Rabbit Kidney ◽  
Renal Tubules ◽  
Similar Response ◽  
Thick Ascending Limb ◽  
Calcium Efflux ◽  
Bathing Medium

Net calcium efflux (JCanet) was compared in isolated perfused cortical and medullary segments of the thick ascending limb of Henle of the rabbit kidney. In response to the addition of calcitonin to the bathing medium, cortical segments showed no change in JCanet, whereas in medullary segments JCanet increased significantly. Similar studies substituting 8-bromo-cyclic AMP (8-BrcAMP) in concentrations of 10(-4) M or lower in the bath showed no effect on JCanet in either segment. When the concentration of 8-BrcAMP in the bath was increased to 10(-3) M, JCanet rose significantly in both segments. These results indicate heterogeneity of response to calcitonin in the cortical and medullary segments of the thick ascending limb of Henle, but a similar response of calcium transport to cAMP. Because we have previously shown that parathyroid hormone stimulates net calcium efflux in the cortical but not in the medullary segments of the thick ascending limb of Henle, the present observations suggest that cAMP may be the mediator of the actions of both calcitonin and parathyroid hormone.

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.

Long-term effects of ACTH combined with angiotensin II on steroidogenesis and adrenal zona glomerulosa morphology in the rat

1987 ◽  
Vol 114 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Anne M. Riondel ◽  
Piera Rebuffat ◽  
Giuseppina Mazzochi ◽  
Gastone G. Nussdorfer ◽  
Rolf C. Gaillard ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Morphological Changes ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Homogeneous Population ◽  
Long Term Treatment ◽  
Acth Treatment ◽  
Glomerulosa Cells ◽  
Zona Glomerulosa Cells

Abstract. To test the hypothesis that the trophic action of angiotensin II on the adrenal zona glomerulosa may allow a sustained stimulation of aldosterone by ACTH by preventing the morphological changes of the zona glomerulosa cells into zona fasciculata-like elements we investigated the effects in rats of a 6-day treatment with ACTH (100 μg/kg/day) alone or combined with angiotensin II (300 ng/kg/day) on corticosterone and aldosterone production and adrenal morphology. The responsiveness of both steroids to an acute ACTH dose was also studied on the last day of long-term treatment. Morphologic data showed that prolonged ACTH treatment stimulated the growth of zona glomerulosa cells, though it transformed the tubulo-lamellar cristae of mitochondria into a homogeneous population of vesicles. Angiotensin II furthered the trophic effects of ACTH but prevented the mitochondrial transformation. Despite its ability to conserve the well differentiated aspect of the zona glomerulosa cells, the administration of angiotensin II was unable to prevent the fall in the secretion of aldosterone caused by chronic ACTH treatment and its subsequent unresponsiveness to ACTH stimulation.

Mechanisms of ACTH- and angiotensin II-stimulated 1α-hydroxycorticosterone secretion in the dogfish, Scyliorhinus canicula

1993 ◽  
Vol 10 (3) ◽  
pp. 235-244 ◽  
Author(s):  
K J Armour ◽  
L B O'Toole ◽  
N Hazon
Keyword(s):  
Angiotensin Ii ◽  
Cyclic Amp ◽  
Intracellular Calcium ◽  
Calcium Concentration ◽  
Extracellular Calcium ◽  
Scyliorhinus Canicula ◽  
Interrenal Gland ◽  
Messenger System ◽  
Dose Dependent Increase ◽  
Dose Dependent

ABSTRACT An isolated perifused interrenal gland preparation from the lesser-spotted dogfish, Scyliorhinus canicula, was used to investigate the mechanisms of action of ACTH and angiotensin II (AII) on elasmobranch adrenocortical cells. ACTH-stimulated 1α-hydroxycorticosterone secretion was unaffected by dantrolene and significantly decreased in the absence of extracellular calcium. Dibutyryl cyclic AMP produced a dose-dependent increase in 1α-hydroxycorticosterone secretion. The results suggest that the mechanism of ACTH action in elasmobranchs may be similar to that reported for mammals and amphibians, involving the synergistic action of calcium with the cyclic AMP messenger system. AII-stimulated 1α-hydroxycorticosterone secretion was significantly inhibited in the presence of dantrolene and in the absence of extracellular calcium, indicating that both extracellular and intracellular calcium are required for the full action of AII. These results are consistent with results in mammals and amphibians where AII stimulates phosphatidylinositol 4,5-bisphosphate hydrolysis and changes in intracellular calcium concentration, and they suggest that AII may operate via this mechanism to stimulate 1α-hydroxycorticosterone secretion in elasmobranchs.

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