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.

scholarly journals Local production and action of adrenomedullin in the rat adrenal zona glomerulosa

1998 ◽  
Vol 156 (3) ◽  
pp. 477-484 ◽  
Author(s):  
S Kapas ◽  
A Martinez ◽  
F Cuttitta ◽  
JP Hinson
Keyword(s):  
In Situ Hybridization ◽  
Inositol Phosphate ◽  
Zona Glomerulosa ◽  
Binding Studies ◽  
Aldosterone Secretion ◽  
Glomerulosa Cells ◽  
Camp Formation ◽  
Zona Glomerulosa Cells

This study was designed to investigate the synthesis and action of adrenomedullin in the rat adrenal gland. The results obtained from in situ hybridization and immunocytochemical studies suggest that adrenomedullin is synthesized not only in the medulla, but also within the zona glomerulosa of the rat adrenal cortex. Findings from in situ hybridization and binding studies also suggested that specific adrenomedullin receptors are expressed in the zona glomerulosa, and that low levels are present in the inner zones of the cortex. The Kd of the zona glomerulosa adrenomedullin receptor (5.5 nmol/l) suggests that it may respond to locally produced adrenomedullin rather than circulating concentrations of the peptide, which are in a lower range. It was found that adrenomedullin acted on zona glomerulosa cells in vitro to stimulate aldosterone release and cAMP formation, but in this tissue did not stimulate inositol phosphate turnover. The effect of adrenomedullin on aldosterone secretion was significantly attenuated by a protein kinase A inhibitor, suggesting that cAMP mediates the effects of adrenomedullin on aldosterone secretion. Adrenomedullin did not significantly affect the response of zona glomerulosa cells to stimulation by either ACTH or angiotensin II. Adrenomedullin did not affect the release of catecholamines, either adrenaline or noradrenaline, by intact adrenal capsular tissue. These data suggest that both adrenomedullin and its specific receptor are expressed in the rat adrenal zona glomerulosa, leading to the hypothesis that adrenomedullin may have an autocrine/paracrine role in the regulation of the rat adrenal zona glomerulosa.

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.

Effects of prolactin on aldosterone secretion in rat zona glomerulosa cells

1999 ◽  
Vol 72 (2) ◽  
pp. 286-293 ◽  
Author(s):  
Mei-Mei Kau ◽  
Ming-Jae Lo ◽  
Shiow-Chwen Tsai ◽  
Jiann-Jong Chen ◽  
Hsiao-Fung Pu ◽  
...  
Keyword(s):  
Zona Glomerulosa ◽  
Aldosterone Secretion ◽  
Glomerulosa Cells ◽  
Zona Glomerulosa Cells

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.

Downregulation of adrenal atrial natriuretic peptide receptor mRNAs and proteins by pregnancy in rats

1997 ◽  
Vol 155 (3) ◽  
pp. 523-530 ◽  
Author(s):  
P Vaillancourt ◽  
S Omer ◽  
R Palfree ◽  
DR Varma ◽  
S Mulay
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Receptor Proteins ◽  
Glomerulosa Cells ◽  
Anp Receptors ◽  
Receptor Mrnas ◽  
Zona Glomerulosa Cells ◽  
Atrial Natriuretic

The main objective of this study was to find out if the reported changes in the aldosterone-suppressant activity of atrial natriuretic peptide (ANP) during different hormonal states in rats are due to a modulation of ANP receptors. In zona glomerulosa cells, ribonuclease protection assay detected mRNAs for guanylate cyclase (GC)-coupled ANP GC-A and GC-B receptors, and for ANP C receptors, which are not coupled to GC. Western analysis using polyclonal anti-GC-A and anti-GC-B receptor antibodies revealed the presence of GC-A but not GC-B receptor proteins in zona glomerulosa cells. Pregnancy (days 7, 16 and 21), oestradiol-17 beta and progesterone decreased mRNAs for all the three ANP receptors in zona glomerulosa cells. Pregnancy decreased GC-A receptor proteins in zona glomerulosa cells, but these recovered to virgin values on day 2 postpartum. ANP receptor mRNAs in zona glomerulosa cells increased by postpartum day 2, but did not reach the values found in virgin rats. Zona fasciculata mainly contained GC-A receptor mRNA. It is concluded that ANP receptors in rat adrenal zona glomerulosa are modulated by pregnancy, oestrogen and progesterone; a decrease in ANP GC-A receptors during pregnancy might explain the accompanying decrease in the aldosterone-suppressant effects of ANP.

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