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

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.

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

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.


1974 ◽  
Vol 185 (1081) ◽  
pp. 375-407 ◽  

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.


1981 ◽  
Vol 61 (5) ◽  
pp. 541-551 ◽  
Author(s):  
B. C. Williams ◽  
J. G. McDougall ◽  
J. F. Tait ◽  
S. A. S. Tait

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.


1982 ◽  
Vol 94 (2) ◽  
pp. 211-224 ◽  
Author(s):  
D. J. Campbell

The role of the composition of the incubation medium in determining the steroidogenic responsiveness of collagenase-dispersed rat zona glomerulosa cells was examined by studying the effect on production of aldosterone and corticosterone of (1) changes in the bovine serum albumin (BSA) concentration in Krebs–Ringer bicarbonate buffer (KRBGA), (2) dialysis of the BSA and (3) comparison of KRBGA with 'modified' Medium 199. Medium 199 was modified so that its electrolytic content was identical to that of KRBGA. Compared with 0·1–0·2% BSA in KRBGA, BSA concentrations of 0·5 and 4% caused inhibition of both basal and K+-stimulated, but not angiotensin II-stimulated steroidogenesis. This inhibitory property of BSA was not removed by dialysis. The BSA did, however, contain a dialysable factor which increased both basal steroidogenesis and the steroidogenic response to maximal K+ and angiotensin II stimulation. Both incubation media contained 0·2% BSA for the comparison of KRBGA with modified Medium 199. Modified Medium 199 increased both basal steroidogenesis and the aldosterone response to K+ stimulation (per cent increase above basal) by two- to threefold compared with KRBGA, with smaller increases in the response to ACTH and 5-hydroxytryptamine (5-HT) and a decrease in the response to cyclic AMP. In contrast, modified Medium 199 increased the aldosterone response to angiotensin II by sevenfold, from 60% (in KRBGA) to 420%. In KRBGA, angiotensin II inhibited K+-stimulated aldosterone production. This effect was produced by concentrations of angiotensin II below the threshold for steroidogenesis and could be reproduced with the angiotensin II antagonist [Sar1, Ileu8]-angiotensin II. Angiotensin II did not inhibit K+-stimulated aldosterone production in modified Medium 199. These data emphasize the importance of the composition of the incubation medium in determining the steroidogenic responsiveness of rat zona glomerulosa cells in vitro. Furthermore, these data indicate that the steroidogenic response to angiotensin II, compared with K+, ACTH, 5-HT and cyclic AMP, is more readily influenced by other, as yet unidentified, factors in the incubation medium, and are consistent with recent evidence that angiotensin II and K+ do not share a common mode of action on steroidogenesis by these 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 ◽  
...  

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


Endocrinology ◽  
2006 ◽  
Vol 147 (2) ◽  
pp. 891-898 ◽  
Author(s):  
Damian G. Romero ◽  
Gaston R. Vergara ◽  
Zheng Zhu ◽  
Gina S. Covington ◽  
Maria W. Plonczynski ◽  
...  

The adrenal gland secretes several cytokines, and cytokines modulate steroid secretion by this gland. In this study, a survey of cytokine production by H295R human adrenocortical cells demonstrated that these cells secreted IL-2, IL-4, IL-8, IL-10, IL-13, and TNFα but not IL-5, IL-12, or interferon-γ. IL-8 was the IL secreted at higher concentration. IL-8 secretion, its regulation, and role in steroidogenesis were further studied. Secreted ILs and steroids were measured by ELISA in cell culture supernatant. IL-8 mRNA was quantified by real-time RT-PCR. H295R cells and human adrenal gland expressed IL-8 mRNA. Angiotensin II, potassium, endothelin-1, IL-1α, IL-1β, TNFα, and Escherichia coli lipopolysaccharide dose-dependently increase IL-8 secretion by H295R cells after 24 h incubation. IL-6 had no effect on IL-8 secretion. Angiotensin II time-dependently increased IL-8 secretion by H295R cells up to 48 h. Angiotensin II caused a biphasic increase in IL-8 mRNA expression with a peak 6 h after stimulation. TNFα synergized angiotensin II, potassium, and IL-1α-mediated IL-8 secretion. IL-8 did not modify aldosterone or cortisol secretion by H295R cells under basal or stimulated (angiotensin II or potassium) conditions. In conclusion, it is demonstrated for the first time that human adrenal cells expressed and secreted IL-8 under the regulation of angiotensin II, potassium, endothelin-1, and immune peptides. Adrenal-secreted IL-8 is one point of convergence between the adrenal gland and the immune system and may have relevance in physiological and pathophysiological conditions associated with increased levels of aldosterone secretagogues and the immune system.


1983 ◽  
Vol 104 (1) ◽  
pp. 103-109 ◽  
Author(s):  
Wolfgang Belmega ◽  
Wolfgang Oelkers ◽  
Lutz Belkien ◽  
Monika Shirpai ◽  
Ulrich Fiedler ◽  
...  

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.


1996 ◽  
Vol 271 (3) ◽  
pp. F709-F716 ◽  
Author(s):  
D. Z. Wang ◽  
Q. Song ◽  
L. M. Chen ◽  
L. Chao ◽  
J. Chao

The tissue kallikrein-kinin system has been implicated in regulating blood pressure and electrolyte homeostasis. To understand the function of this system, we identified the expression and cellular localization of its components including tissue kallikrein, kallistatin, kininogen, and bradykinin B1 and B2 receptors in human adrenal gland. Reverse transcription-polymerase chain reaction followed by Southern blot analysis showed that these five components of this system were all expressed in human adrenal gland. In situ hybridization histochemistry with respective digoxigenin-labeled antisense riboprobes revealed localization of kallikrein transcript throughout the adrenal cortex and medulla except the zona glomerulosa, whereas kallistatin mRNA was only localized in the zona fasciculata. Low-molecular-weight kininogen and B2 receptor mRNAs were colocalized in the zona glomerulosa and zona fasciculata and also in the zona reticularis and chromaffin cells but to a lesser degree. The B1 receptor mRNA was stained in the zona fasciculata and medulla. These results show the expression and differential colocalization of the components of the tissue kallikrein-kinin system and reveal the potential action sites of this system in the adrenal gland.


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.


1994 ◽  
Vol 14 (5) ◽  
pp. 3469-3483 ◽  
Author(s):  
I J Davis ◽  
L F Lau

nurr77 and nurr-1 are growth factor-inducible members of the steroid/thyroid hormone receptor gene superfamily. In order to gain insight into the potential roles of nur77 in the living organism, we used pharmacologic treatments to examine the expression of nur77 in the mouse adrenal gland. We found that nur77 and nurr-1 are induced in the adrenal gland upon treatment with pentylene tetrazole (Ptz; Metrazole). This induction is separable into distinct endocrine and neurogenic mechanisms. In situ hybridization analysis demonstrates that nur77 expression upon Ptz treatment in the adrenal cortex is localized primarily to the inner cortical region, the zona fasciculata-reticularis, with minimal induction in the zona glomerulosa. This induction is inhibitable by pretreatment with dexamethasone, indicating involvement of the hypothalamic-pituitary-adrenal axis in the activation of adrenal cortical expression. When mice were injected with adrenocorticotrophic hormone (ACTH), nur77 expression in the adrenal gland spanned all cortical layers including the zona glomerulosa, but medullary expression was not induced. Ptz also induces expression of both nur77 and nurr-1 in the adrenal medulla. Medullary induction is likely to have a neurogenic origin, as nur77 expression was not inhibitable by dexamethasone pretreatment and induction was seen after treatment with the cholinergic neurotransmitter nicotine. nur77 is also inducible by ACTH, forskolin, and the second messenger analog dibutyryl cyclic AMP in the ACTH-responsive adrenal cortical cell line Y-1. Significantly, Nur77 isolated from ACTH-stimulated Y-1 cells bound to its response element whereas Nur77 present in unstimulated cells did not. Moreover, Nur77 in ACTH-treated Y-1 cells was hypophosphorylated at serine 354 compared with that in untreated cells. These results, taken together with the previous observation that dephosphorylation of serine 354 affects DNA binding affinity in vitro, show for the first time that phosphorylation of Nur77 at serine 354 is under hormonal regulation, modulating its DNA binding affinity. Thus, ACTH regulates Nur77 in two ways: activation of its gene and posttranslational modification. A promoter analysis of nur77 induction in Y-1 cells indicates that the regulatory elements mediating ACTH induction differ from those required for induction in the adrenal medullary tumor cell line PC12 and in 3T3 fibroblasts.


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