Effect of CO2/pH on the aldosterone response to hypoxia in bovine adrenal cells in vitro

1993 ◽  
Vol 265 (4) ◽  
pp. R820-R825
Author(s):  
H. Raff ◽  
B. Jankowski
Keyword(s):  
Respiratory Acidosis ◽  
Inhibitory Effect ◽  
Zona Glomerulosa ◽  
Ang Ii ◽  
Adrenal Cells ◽  
Aldosterone Production ◽  
Per Se ◽  
Air Control

Acidosis increases and hypoxia decreases aldosterone production from the adrenal zona glomulerosa in vivo, in situ, and in vitro. These effects appear to be located at different steps in the steroidogenic process. Because respiratory acidosis and hypoxemia are common sequelae of chronic lung disease, the present experiments evaluated the interaction of hypoxia and CO2 (with uncompensated or compensated extracellular pH) on aldosteronogenesis in vitro. Bovine adrenal zona glomerulosa cells were stimulated with angiotensin II (ANG II) or adenosine 3',5'-cyclic monophosphate under room air control (21% O2-0% CO2), CO2 per se (21% O2-10% CO2), hypoxia per se (10% O2-0% CO2), and the combination of CO2 and hypoxia (10% O2-10% CO2). Furthermore, under CO2, pH was either allowed to decrease from 7.2 to 6.8 (uncompensated) or its decrease was minimized (> 7.05) with NaOH (compensated). CO2 without pH compensation led to a significant increase in ANG II-stimulated aldosterone release; when the decrease in pH was minimized, CO2 inhibited ANG II-stimulated aldosterone release. Hypoxia inhibited aldosterone release; the inhibitory effect of hypoxia predominated when combined with CO2. In the presence of cyanoketone, pregnenolone production from endogenous precursors (early pathway) was unaffected. However, the conversion of corticosterone to aldosterone (late pathway) was inhibited by low O2 but unaffected by CO2. It is concluded that the inhibitory effect of low O2 on the late pathway predominates over the effects of uncompensated or compensated simulated respiratory acidosis on aldosteronogenesis.

Effects of corticostatin-I on rat adrenal cells in vitro

1990 ◽  
Vol 125 (2) ◽  
pp. 287-292 ◽  
Author(s):  
T. Tominaga ◽  
J. Fukata ◽  
Y. Naito ◽  
Y. Nakai ◽  
S. Funakoshi ◽  
...  
Keyword(s):  
Specific Binding ◽  
Corticosterone Level ◽  
Inhibitory Effect ◽  
Zona Glomerulosa ◽  
Dependent Manner ◽  
Minimum Effective Concentration ◽  
Adrenal Cells ◽  
Aldosterone Production ◽  
The Media

ABSTRACT We have examined the mechanism by which corticostatin-I (CS-I) acts to attenuate ACTH-induced steroidogenesis in rat adrenal cells. CS-I inhibited ACTH-induced corticosterone production in a dosedependent manner, without any effects on the basal corticosterone level in adrenal cells. When the cells were stimulated by 100 pg ACTH/ml, the minimum effective concentration of CS-I was 100 ng/ml, and 0.3–1.0 μg CS-I/ml produced a 50% reduction of the stimulated corticosterone production. The inhibitory effect of CS-I on ACTH-stimulated corticosterone production became apparent within 15 min of incubation, and the effect was reversed quickly by the removal of CS-I from the media. CS-I had no effect on angiotensin II-stimulated aldosterone production by adrenal zona glomerulosa cells. CS-I also did not affect cyclic AMP- or forskolin-stimulated corticosterone production. In an in-vitro binding study using 125I-labelled CS-I, CS-I showed considerable specific binding to rat adrenal cells, and the binding competed with ACTH in a dose-dependent manner. These experiments suggest that CS-I competes with ACTH on their binding sites and exerts an inhibitory effect on the adrenal cells. Journal of Endocrinology (1990) 125, 287–292

The actions of N-terminal fragments of corticotrophin on steroidogenesis in dispersed rat adrenal cells in vitro

1986 ◽  
Vol 109 (2) ◽  
pp. 275-278 ◽  
Author(s):  
G. P. Vinson ◽  
B. J. Whitehouse ◽  
A. Bateman ◽  
A. Dell ◽  
S. M. Laird
Keyword(s):  
Sodium Intake ◽  
Physiological Role ◽  
Cell Types ◽  
Structural Features ◽  
Zona Glomerulosa ◽  
Minimum Effective Concentration ◽  
Adrenal Cells ◽  
Aldosterone Production

ABSTRACT The finding that the rat adrenal zona glomerulosa cell shows specific sensitivity to stimulation by α-MSH and related peptides has been confirmed both in vivo and in vitro, raising the possibility that α-MSH may have a physiological role in the control of glomerulosa function and aldosterone secretion. To define more closely the structural features which confer the specificity of the glomerulosa response, other ACTH derived peptides have been tested for their specificity of actions on rat adrenal cells in vitro. The peptides tested were ACTH(5–24), ACTH(1–12), ACTH(1–14), ACTH(1–15), ACTH1–16) and ACTH(1–17). Their actions were compared with those of α-MSH and ACTH(1–24). All of the ACTH-derived peptides stimulated glomerulosa corticosterone production with sensitivities similar to that of α-MSH; minimum effective concentration was 10 nmol/l. Also, like α-MSH, the shorter ACTH peptides stimulated aldosterone production only relatively weakly in these cells from animals on normal sodium intake. Only ACTH(5–24), ACTH(1–16) and ACTH(1–17) stimulated fasciculata/reticularis cells at concentrations up to 1 μmol/l. The actions of all of the shorter peptides were thus unlike those of ACTH(1–24) which stimulates both cell types with approximately equal sensitivity, and which furthermore strongly stimulates aldosterone production. The data suggest that the 18–24 region of the ACTH molecule contains the signal for a fasciculata/ reticularis response, and the region 1–13 that for glomerulosa specificity. They confirm the view that, in the rat, α-MSH itself may be the specific pituitary glomerulosa-stimulating agent which much experimental work has predicted. They also indicate that synthetic ACTH(1–17) analogues should be used with caution. J. Endocr. (1986) 109, 275–278

scholarly journals The Orphan Nuclear Receptors NURR1 and NGFIB Regulate Adrenal Aldosterone Production

2004 ◽  
Vol 18 (2) ◽  
pp. 279-290 ◽  
Author(s):  
Mary H. Bassett ◽  
Takashi Suzuki ◽  
Hironobu Sasano ◽  
Perrin C. White ◽  
William E. Rainey
Keyword(s):  
Kinase Inhibitor ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Related Factor ◽  
Mrna Levels ◽  
Ang Ii ◽  
Orphan Nuclear Receptors ◽  
Protein Levels ◽  
Aldosterone Production

Abstract Aldosterone biosynthesis in the zona glomerulosa of the adrenal cortex is regulated by transcription of CYP11B2 (encoding aldosterone synthase). The effects of nerve growth factor-induced clone B (NGFIB) (NR4A1), Nur-related factor 1 (NURR1) (NR4A2), and steroidogenic factor-1 (SF-1) (NR5A1) on transcription of human CYP11B2 (hCYP11B2) and hCYP11B1 (11β-hydroxylase) were compared in human H295R adrenocortical cells. hCYP11B2 expression was increased by NGFIB and NURR1. Although hCYP11B1 was activated by SF-1, cotransfection with SF-1 inhibited activation of hCYP11B2 by NGFIB and NURR1. NGFIB and NURR1 transcript and protein levels were strongly induced by angiotensin (Ang) II, the major regulator of hCYP11B2 expression in vivo. Sequential deletion and mutagenesis of the hCYP11B2 promoter identified two functional NGFIB response elements (NBREs), one located at −766/−759 (NBRE-1) and the previously studied Ad5 element at −129/−114. EMSAs suggested that both elements bound NGFIB and NURR1. In human adrenals, NURR1 immunoreactivity was preferentially localized in the zona glomerulosa and to a lesser degree in the zona fasciculata, whereas NGFIB was detected in both zones. The calmodulin kinase inhibitor KN93 partially blocked K+-stimulated transcription of NGFIB and NURR1. KN93 partially inhibited the effect of Ang II on NURR1 mRNA levels but did not modify the effect on expression of NGFIB. Mutation of the NBRE-1, Ad5, and Ad1/cAMP response element (CRE) cis-elements reduced both basal and Ang II-induced levels of hCYP11B2, demonstrating that all three elements are important for maximal transcriptional activity. Our results suggest that NGFIB and NURR1 are key regulators of hCYP11B2 expression and may partially mediate the regulation of hCYP11B2 by Ang II.

scholarly journals GRK2-Mediated Crosstalk Between β-Adrenergic and Angiotensin II Receptors Enhances Adrenocortical Aldosterone Production In Vitro and In Vivo

2020 ◽  
Vol 21 (2) ◽  
pp. 574
Author(s):  
Celina M. Pollard ◽  
Jennifer Ghandour ◽  
Natalie Cora ◽  
Arianna Perez ◽  
Barbara M. Parker ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
G Protein ◽  
Adrenal Cortex ◽  
Zona Glomerulosa ◽  
Type I ◽  
Signaling Crosstalk ◽  
Aldosterone Production ◽  
Steroidogenic Acute Regulatory

Aldosterone is produced by adrenocortical zona glomerulosa (AZG) cells in response to angiotensin II (AngII) acting through its type I receptors (AT1Rs). AT1R is a G protein-coupled receptor (GPCR) that induces aldosterone via both G proteins and the adapter protein βarrestin1, which binds the receptor following its phosphorylation by GPCR-kinases (GRKs) to initiate G protein-independent signaling. β-adrenergic receptors (ARs) also induce aldosterone production in AZG cells. Herein, we investigated whether GRK2 or GRK5, the two major adrenal GRKs, is involved in the catecholaminergic regulation of AngII-dependent aldosterone production. In human AZG (H295R) cells in vitro, the βAR agonist isoproterenol significantly augmented both AngII-dependent aldosterone secretion and synthesis, as measured by the steroidogenic acute regulatory (StAR) protein and CYP11B2 (aldosterone synthase) mRNA inductions. Importantly, GRK2, but not GRK5, was indispensable for the βAR-mediated enhancement of aldosterone in response to AngII. Specifically, GRK2 inhibition with Cmpd101 abolished isoproterenol’s effects on AngII-induced aldosterone synthesis/secretion, whereas the GRK5 knockout via CRISPR/Cas9 had no effect. It is worth noting that these findings were confirmed in vivo, since rats overexpressing GRK2, but not GRK5, in their adrenals had elevated circulating aldosterone levels compared to the control animals. However, treatment with the β-blocker propranolol prevented hyperaldosteronism in the adrenal GRK2-overexpressing rats. In conclusion, GRK2 mediates a βAR-AT1R signaling crosstalk in the adrenal cortex leading to elevated aldosterone production. This suggests that adrenal GRK2 may be a molecular link connecting the sympathetic nervous and renin-angiotensin systems at the level of the adrenal cortex and that its inhibition might be therapeutically advantageous in hyperaldosteronism-related conditions.

Aldosterone release from adrenal cells is inhibited by reduced oxygen levels in vitro during maturation in rabbits

1996 ◽  
Vol 8 (8) ◽  
pp. 1131 ◽  
Author(s):  
PE Papanek ◽  
BM Jankowski ◽  
H Raff
Keyword(s):  
Acute Hypoxia ◽  
Specific Effect ◽  
Adrenocorticotrophic Hormone ◽  
Adrenal Cells ◽  
New Zealand White Rabbits ◽  
Aldosterone Production ◽  
Different Levels ◽  
In Cells

Hypoxia in vivo leads to a decrease in aldosterone not completely explained by extrinsic controllers of adrenal function including adrenocorticotrophic hormone, renin-angiotensin II, and K+. The dissociation of renin and aldosterone during acute hypoxia in vivo may be explained by the finding that aldosterone synthesis in adrenal cells is reversibly and specifically inhibited by decreases in O2 levels within the physiological range. The present study investigated whether the direct effect of acute decreases in O2 levels on aldosteronogenic pathway is altered during maturation. Adrenal cells (whole adrenals) were prepared from fetal (27 days gestation), neonatal (1 day), and infant (10 days) New Zealand White rabbits, and capsular cells were prepared from young (21 days) and adult (3 months) rabbits. All cells were dispersed with collagenase. Basal and cAMP-stimulated aldosterone production were assessed under two different levels of O2 (pO2 = 20.0 kPa or pO2 = 8.7 kPa). Decreased O2 levels significantly inhibited cAMP-stimulated aldosterone production in cells obtained from rabbits of all ages by 60 +/- 5% cAMP-stimulated aldosterone production was significantly lower in cells obtained from neonates and premature animals under both normoxic and reduced O2 conditions as compared with animals > or = 10 days old. Corticosterone production by cells obtained from adults and 21-day-old rabbits was unaffected by reduced O2 conditions suggesting a specific effect on the aldosterone pathway. The data demonstrate that the O2 sensitivity of the aldosterone pathway is present throughout development.

scholarly journals Targeted disruption of the Kcnj5 gene in the female mouse lowers aldosterone levels

2018 ◽  
Vol 132 (1) ◽  
pp. 145-156 ◽  
Author(s):  
Iris Hardege ◽  
Lu Long ◽  
Raya Al Maskari ◽  
Nicola Figg ◽  
Kevin M. O’Shaughnessy
Keyword(s):  
Zona Glomerulosa ◽  
K Channel ◽  
Peroxisome Proliferator ◽  
Aldosterone Secretion ◽  
Gene Encoding ◽  
Peroxisome Proliferator Activated Receptor ◽  
Adrenal Cells ◽  
Aldosterone Production ◽  
Inwardly Rectifying

Aldosterone is released from adrenal zona glomerulosa (ZG) cells and plays an important role in Na and K homoeostasis. Mutations in the human inwardly rectifying K channel CNJ type (KCNJ) 5 (KCNJ5) gene encoding the G-coupled inwardly rectifying K channel 4 (GIRK4) cause abnormal aldosterone secretion and hypertension. To better understand the role of wild-type (WT) GIRK4 in regulating aldosterone release, we have looked at aldosterone secretion in a Kcnj5 knockout (KO) mouse. We found that female but not male KO mice have reduced aldosterone levels compared with WT female controls, but higher levels of aldosterone after angiotensin II (Ang-II) stimulation. These differences could not be explained by sex differences in aldosterone synthase (Cyp11B2) gene expression in the mouse adrenal. Using RNAseq analysis to compare WT and KO adrenals, we showed that females also have a much larger set of differentially expressed adrenal genes than males (395 compared with 7). Ingenuity Pathway Analysis (IPA) of this gene set suggested that peroxisome proliferator activated receptor (PPAR) nuclear receptors regulated aldosterone production and altered signalling in the female KO mouse, which could explain the reduced aldosterone secretion. We tested this hypothesis in H295R adrenal cells and showed that the selective PPARα agonist fenofibrate can stimulate aldosterone production and induce Cyp11b2. Dosing mice in vivo produced similar results. Together our data show that Kcnj5 is important for baseline aldosterone secretion, but its importance is sex-limited at least in the mouse. It also highlights a novel regulatory pathway for aldosterone secretion through PPARα that may have translational potential in human hyperaldosteronism.

O2 dependence of pregnenolone and aldosterone synthesis in mitochondria from bovine zona glomerulosa cells

1995 ◽  
Vol 78 (5) ◽  
pp. 1625-1628 ◽  
Author(s):  
H. Raff ◽  
B. Jankowski
Keyword(s):  
Energy Production ◽  
Zona Glomerulosa ◽  
Mitochondrial Enzymes ◽  
Isolated Mitochondria ◽  
Aldosterone Production ◽  
Glomerulosa Cells ◽  
Air Control ◽  
Electron Transport Proteins ◽  
Zona Glomerulosa Cells

Hypoxia in vivo results in a decrease in aldosterone not accounted for by extra-adrenal controllers. We have demonstrated that aldosteronogenesis but not cortisol synthesis in the whole cell is O2 sensitive. In the intact glomerulosa cell, this sensitivity is located in the late pathway step catalyzed by conversion of corticosterone to aldosterone (P-450aldo), whereas the early pathway catalyzed by conversion of cholesterol to pregnenolone (P-450scc) is not inhibited until PO2 is very low. Because P-450aldo and P-450scc are mitochondrial enzymes that depend on the same NADPH-specific electron transport proteins, we hypothesized that O2 sensitivity would be independent of energy production and expressed in isolated mitochondria. We measured the conversion of exogenous 25(OH)-cholesterol to pregnenolone and of exogenous corticosterone to aldosterone in the presence of cyanoketone in mitochondria isolated from bovine zona glomerulosa cells and exposed to an experimental gas (1–100% O2) vs. a room air control. Pregnenolone production was not affected until PO2 was < 35 Torr and decreased to almost nil when PO2 was < 30 Torr. In contrast, aldosterone production increased under hyperoxia and decreased under moderate decreases in O2. The conversion of corticosterone to aldosterone was maintained at approximately 50% of control, even when PO2 was < 20 Torr. The sensitivity of the aldosterone pathway to changes in O2 within the physiological range appears to reside in the mitochondrial late pathway (i.e., P-450aldo) and is not significantly influenced by cytosolic regulators of steroidogenesis or by limitation of reducing equivalents.

Abstract 198: Angiotensin II Inhibits Cardiac Angiogenesis via the Cooperation of p53 and Jagged 1

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Aili Guan ◽  
Hui Gong ◽  
Yong Ye ◽  
Jianguo Jia ◽  
Guoping Zhang ◽  
...  
Keyword(s):  
Hypoxia Inducible Factor ◽  
Underlying Mechanism ◽  
Inhibitory Effect ◽  
Tube Formation ◽  
Ang Ii ◽  
Capillary Formation ◽  
Angiogenic Effect ◽  
Endothelial Growth Factor

It is well established that angiotension II (Ang II) is an important regulator in vascular homeostasis. Under certain conditions, Ang II could exert anti-angiogenic effects in cardiovascular system. However, the potential mechanism is unclear. P53 has been reported to suppress angiogenesis by promoting hypoxia-inducible factor-1 (Hif-1α) degradation. This study was conducted to determine the contribution of P53 and the underlying mechanism to the anti-angiogenic effect of Ang II. Angiogenesis was determined by tube formation from the cardiac microvascular endothelial cells (ECs). Microvessel density and cardiac function were analyzed in mice subjected to Ang II infusion (200 ng/kg/min ) or vehicle for 2 weeks. Ang II (1μM) greatly inhibited tube formation and stimulated phosphorylation and upregulation of P53 in cultured cardiac ECs. P53 inhibitor, pifithrin-α (PFT-α,3.0mg/kg), significantly reversed the inhibitory effect of Ang II on tube formation. Vascular endothelial growth factor (VEGF ) and Hif-1α has been reported as important pro-angiogenetic factors. The present study indicated that Ang II decreased VEGF concentration in cultured medium and downregulated Hif-1α expression in cultured ECs. Interestingly, Ang II also stimulated the upregulation of Jagged 1, a ligand of Notch, but it didn't affect the Delta-like 4 (Dll 4) , another ligand of Notch, expression in cardiac ECs. However, PFT-α partly abolished these effects of Ang II. These results were consistent with the study in vivo. Further research revealed that siRNA-Jagged 1 transfection in cultured ECs dramatically abolished the phosphorylation of P53 and the downregulation of Hif-1α induced by Ang II. Additionally, Ang II- induced inhibitory effect on capillary formation was blocked by siRNA-Jagged 1 transfection in cultured cardiac ECs. In conclusion, Ang II promoted the phosphorylation and upregulation of P53, and increased Jagged 1 expression, the upregulation of Jagged 1 in turn stimulated the phosphorylation of P53, which resulted in the downregulation of Hif-1α and VEGF, then induced the inhibitory effects of Ang II on capillary formation. The present data suggest that Ang II exerts anti-angiogenesis via the cooperation of P53 and Jagged 1 in vitro and in vivo.

Regulation of aldosterone production from zona glomerulosa cells by ANG II and cAMP: evidence for PKA-independent activation of CaMK by cAMP

2006 ◽  
Vol 290 (3) ◽  
pp. E423-E433 ◽  
Author(s):  
Stepan Gambaryan ◽  
Elke Butt ◽  
Piet Tas ◽  
Albert Smolenski ◽  
Bruno Allolio ◽  
...  
Keyword(s):  
Intracellular Signaling ◽  
Mapk Signaling ◽  
Zona Glomerulosa ◽  
Intracellular Camp ◽  
Ang Ii ◽  
Intact Cells ◽  
Molecular Events ◽  
Aldosterone Production ◽  
Dependent Protein

Aldosterone production in zona glomerulosa (ZG) cells of adrenal glands is regulated by various extracellular stimuli (K+, ANG II, ACTH) that all converge on two major intracellular signaling pathways: an increase in cAMP production and calcium (Ca2+) mobilization. However, molecular events downstream of the increase in intracellular cAMP and Ca2+ content are controversial and far from being completely resolved. Here, we found that Ca2+/calmodulin-dependent protein kinases (CaMKs) play a predominant role in the regulation of aldosterone production stimulated by ANG II, ACTH, and cAMP. The specific CaMK inhibitor KN93 strongly reduced ANG II-, ACTH-, and cAMP-stimulated aldosterone production. In in vitro kinase assays and intact cells, we could show that cAMP-induced activation of CaMK, using the adenylate cyclase activator forskolin or the cAMP-analog Sp-5,6-DCI-cBIMPS (cBIMPS), was not mediated by PKA. Activation of the recently identified cAMP target protein Epac (exchange protein directly activated by cAMP) by 8-pCPT-2′- O-Me-cAMP had no effect on CaMK activity and aldosterone production. Furthermore, we provide evidence that cAMP effects in ZG cells do not involve Ca2+ or MAPK signaling. Our results suggest that ZG cells, in addition to PKA and Epac/Rap proteins, contain other as yet unidentified cAMP mediator(s) involved in regulating CaMK activity and aldosterone secretion.

scholarly journals Renin knockout rat: control of adrenal aldosterone and corticosterone synthesis in vitro and adrenal gene expression

2015 ◽  
Vol 308 (1) ◽  
pp. R73-R77 ◽  
Author(s):  
Hershel Raff ◽  
Ashley Gehrand ◽  
Eric D. Bruder ◽  
Matthew J. Hoffman ◽  
William C. Engeland ◽  
...  
Keyword(s):  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Immunohistochemical Analysis ◽  
Zona Glomerulosa ◽  
Ang Ii ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Aldosterone Production ◽  
Renin Mrna

The classic renin-angiotensin system is partly responsible for controlling aldosterone secretion from the adrenal cortex via the peptide angiotensin II (ANG II). In addition, there is a local adrenocortical renin-angiotensin system that may be involved in the control of aldosterone synthesis in the zona glomerulosa (ZG). To characterize the long-term control of adrenal steroidogenesis, we utilized adrenal glands from renin knockout (KO) rats and compared steroidogenesis in vitro and steroidogenic enzyme expression to wild-type (WT) controls (Dahl S rat). Adrenal capsules (ZG; aldosterone production) and subcapsules [zona reticularis/fasciculata (ZFR); corticosterone production] were separately dispersed and studied in vitro. Plasma renin activity and ANG II concentrations were extremely low in the KO rats. Basal and cAMP-stimulated aldosterone production was significantly reduced in renin KO ZG cells, whereas corticosterone production was not different between WT and KO ZFR cells. As expected, adrenal renin mRNA expression was lower in the renin KO compared with the WT rat. Real-time PCR and immunohistochemical analysis showed a significant decrease in P450aldo ( Cyp11b2) mRNA and protein expression in the ZG from the renin KO rat. The reduction in aldosterone synthesis in the ZG of the renin KO adrenal seems to be accounted for by a specific decrease in P450aldo and may be due to the absence of chronic stimulation of the ZG by circulating ANG II or to a reduction in locally released ANG II within the adrenal gland.

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