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Shefer G, Marcus Y, Knoll E, Dolkart O, Foichtwanger S, Nevo N, Limor R, Stern N. Angiotensin 1-7 Is a Negative Modulator of Aldosterone Secretion In Vitro and In Vivo. Hypertension 2016; 68:378-84. [PMID: 27245181 DOI: 10.1161/hypertensionaha.116.07088] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/03/2016] [Indexed: 11/16/2022]
Abstract
Angiotensin (1-7) [Ang 1-7] is a 7 amino acid peptide generated predominantly from Ang II by the action of Ang-converting enzyme 2. We previously showed that Ang 1-7 reduced plasma aldosterone and plasma renin activity in high fructose-fed rats, and that the reduction in circulating aldosterone seemed to accord a parallel reduction in plasma renin activity. Here, we tested the possibility that Ang 1-7 affects aldosterone secretion acting directly in glomerulosa cells. First, as detected by immunofluorescence, the receptor for Ang 1-7, Mas1 is localized predominantly at the rat adrenal subcapsular region. Second, in isolated rat glomerulosa cells incubates, Ang 1-7 attenuated the aldosterone response to Ang II, with the strongest effect seen on Ang II (10(-9) M) (control 22±2.5 pg/10(5) cells; Ang II [10(-9) M] 189±11 pg/10(5) cells; Ang II [10(-9) M]+Ang 1-7 [10(-6) M] 33±3.6 pg/10(5) cells; P<0.001) and the largest effect on adrenocorticotropic hormone (10(-8) M) (control 30±3.4 pg/10(5) cells; ACTH [10(-8) M] 409±32.5 pg/10(5) cells; ACTH [10(-8) M]+Ang 1-7 [10(-6) M] 280±12.5 pg/10(5) cells; P<0.001). In contrast, Ang 1-7 did not affect the aldosterone response to potassium (K(+)). In rats subjected to a low-salt diet for 7 days, continuous infusion of Ang 1-7 (576 μg/kg per day) resulted in a lesser rise in aldosterone (salt deplete+Ang 1-7, 16.4±4.8 ng/dL) compared with rats receiving vehicle (salt deplete+vehicle, 27.6±5.3 ng/dL; P<0.01) but did not modify plasma renin activity. Taken together, these results indicate that Ang 1-7 can act as a negative modulator of aldosterone secretion in vitro and in vivo.
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Affiliation(s)
- Gabi Shefer
- From the Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center Medical Center and Sackler Faculty of Medicine, Tel Aviv, Israel (G.S., Y.M., E.K., S.F., R.L., N.S.); Division of Orthopedic Surgery, Shoulder Unit, Tel Aviv Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel (O.D.); and Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel (N.N.)
| | - Yonit Marcus
- From the Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center Medical Center and Sackler Faculty of Medicine, Tel Aviv, Israel (G.S., Y.M., E.K., S.F., R.L., N.S.); Division of Orthopedic Surgery, Shoulder Unit, Tel Aviv Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel (O.D.); and Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel (N.N.)
| | - Esther Knoll
- From the Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center Medical Center and Sackler Faculty of Medicine, Tel Aviv, Israel (G.S., Y.M., E.K., S.F., R.L., N.S.); Division of Orthopedic Surgery, Shoulder Unit, Tel Aviv Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel (O.D.); and Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel (N.N.)
| | - Oleg Dolkart
- From the Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center Medical Center and Sackler Faculty of Medicine, Tel Aviv, Israel (G.S., Y.M., E.K., S.F., R.L., N.S.); Division of Orthopedic Surgery, Shoulder Unit, Tel Aviv Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel (O.D.); and Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel (N.N.)
| | - Shulamit Foichtwanger
- From the Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center Medical Center and Sackler Faculty of Medicine, Tel Aviv, Israel (G.S., Y.M., E.K., S.F., R.L., N.S.); Division of Orthopedic Surgery, Shoulder Unit, Tel Aviv Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel (O.D.); and Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel (N.N.)
| | - Nava Nevo
- From the Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center Medical Center and Sackler Faculty of Medicine, Tel Aviv, Israel (G.S., Y.M., E.K., S.F., R.L., N.S.); Division of Orthopedic Surgery, Shoulder Unit, Tel Aviv Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel (O.D.); and Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel (N.N.)
| | - Rona Limor
- From the Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center Medical Center and Sackler Faculty of Medicine, Tel Aviv, Israel (G.S., Y.M., E.K., S.F., R.L., N.S.); Division of Orthopedic Surgery, Shoulder Unit, Tel Aviv Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel (O.D.); and Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel (N.N.)
| | - Naftali Stern
- From the Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center Medical Center and Sackler Faculty of Medicine, Tel Aviv, Israel (G.S., Y.M., E.K., S.F., R.L., N.S.); Division of Orthopedic Surgery, Shoulder Unit, Tel Aviv Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel (O.D.); and Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel (N.N.).
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Abstract
The purpose of this article is to review fundamentals in adrenal gland histophysiology. Key findings regarding the important signaling pathways involved in the regulation of steroidogenesis and adrenal growth are summarized. We illustrate how adrenal gland morphology and function are deeply interconnected in which novel signaling pathways (Wnt, Sonic hedgehog, Notch, β-catenin) or ionic channels are required for their integrity. Emphasis is given to exploring the mechanisms and challenges underlying the regulation of proliferation, growth, and functionality. Also addressed is the fact that while it is now well-accepted that steroidogenesis results from an enzymatic shuttle between mitochondria and endoplasmic reticulum, key questions still remain on the various aspects related to cellular uptake and delivery of free cholesterol. The significant progress achieved over the past decade regarding the precise molecular mechanisms by which the two main regulators of adrenal cortex, adrenocorticotropin hormone (ACTH) and angiotensin II act on their receptors is reviewed, including structure-activity relationships and their potential applications. Particular attention has been given to crucial second messengers and how various kinases, phosphatases, and cytoskeleton-associated proteins interact to ensure homeostasis and/or meet physiological demands. References to animal studies are also made in an attempt to unravel associated clinical conditions. Many of the aspects addressed in this article still represent a challenge for future studies, their outcome aimed at providing evidence that the adrenal gland, through its steroid hormones, occupies a central position in many situations where homeostasis is disrupted, thus highlighting the relevance of exploring and understanding how this key organ is regulated. © 2014 American Physiological Society. Compr Physiol 4:889-964, 2014.
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Affiliation(s)
- Nicole Gallo-Payet
- Division of Endocrinology, Department of Medicine, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, and Centre de Recherche Clinique Étienne-Le Bel of the Centre Hospitalier Universitaire de Sherbrooke (CHUS), Sherbrooke, Quebec, Canada
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Gomez-Sanchez CE, Oki K. Minireview: potassium channels and aldosterone dysregulation: is primary aldosteronism a potassium channelopathy? Endocrinology 2014; 155:47-55. [PMID: 24248457 PMCID: PMC5398635 DOI: 10.1210/en.2013-1733] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Primary aldosteronism is the most common form of secondary hypertension and has significant cardiovascular consequences. Aldosterone-producing adenomas (APAs) are responsible for half the cases of primary aldosteronism, and about half have mutations of the G protein-activated inward rectifying potassium channel Kir3.4. Under basal conditions, the adrenal zona glomerulosa cells are hyperpolarized with negative resting potentials determined by membrane permeability to K(+) mediated through various K(+) channels, including the leak K(+) channels TASK-1, TASK-3, and Twik-Related Potassium Channel 1, and G protein inward rectifying potassium channel Kir3.4. Angiotensin II decreases the activity of the leak K(+) channels and Kir3.4 channel and decreases the expression of the Kir3.4 channel, resulting in membrane depolarization, increased intracellular calcium, calcium-calmodulin pathway activation, and increased expression of cytochrome P450 aldosterone synthase (CYP11B2), the last enzyme for aldosterone production. Somatic mutations of the selectivity filter of the Kir3.4 channel in APA results in loss of selectivity for K(+) and entry of sodium, resulting in membrane depolarization, calcium mobilization, increased CYP11B2 expression, and hyperaldosteronism. Germ cell mutations cause familial hyperaldosteronism type 3, which is associated with adrenal zona glomerulosa hyperplasia, rather than adenoma. Less commonly, somatic mutations of the sodium-potassium ATPase, calcium ATPase, or the calcium channel calcium channel voltage-dependent L type alpha 1D have been found in some APAs. The regulation of aldosterone secretion is exerted to a significant degree by activation of membrane K(+) and calcium channels or pumps, so it is not surprising that the known causes of disorders of aldosterone secretion in APA have been channelopathies, which activate mechanisms that increase aldosterone synthesis.
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Affiliation(s)
- Celso E Gomez-Sanchez
- Endocrinology Division (C.E.G.-S.), G. V. (Sonny) Montgomery Veterans Affairs Medical Center and University of Mississippi Medical Center, Jackson, Mississippi 39216; and Department of Endocrinology and Diabetes (K.O.), Hiroshima University Hospital, Hiroshima 734-8551, Japan
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Pappa T, Papanastasiou L, Koutmos S, Tsiavos V, Roussaki P, Zilos A, Ragkou D, Kaltsas G, Piaditis G. Pattern of adrenal morphology and function in patients with acromegaly. Eur J Clin Invest 2012; 42:275-81. [PMID: 21883185 DOI: 10.1111/j.1365-2362.2011.02580.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Acromegaly is well known to induce hypertrophic and hyperplastic changes in various organs and is commonly accompanied by arterial hypertension. In our study, we assess the adrenal morphology and function in a series of patients with acromegaly and possible associations with the activity of the disease and arterial hypertension. MATERIALS AND METHODS Sixty patients with acromegaly, admitted to two endocrinology departments in the time period 2005-2010, were studied prospectively. Basal IGF-1 and growth hormone levels after oral glucose tolerance test were used to assess the disease activity. All subjects underwent adrenal CT scan, basal adrenal hormonal investigation and evaluation with 24-h urinary free cortisol and cortisol levels following low-dose dexamethasone suppression test. In 33 acromegalics, the 'modified' saline infusion test (MSI), i.e. saline infusion after dexamethasone administration, was performed to identify autonomous aldosterone (ALD) secretion. RESULTS Abnormal adrenal morphology was present in 48% of our patients, and a significant association was found between the presence of arterial hypertension and adrenal morphology. Among patients with adrenal morphological changes, 55% exhibited no adrenal secretory hyperactivity, 34% autonomous cortisol, 7% ALD and 4% combined autonomous cortisol and ALD secretion, when applying recently proposed modified cut-off levels compared to widely used criteria. An increased prevalence of autonomous ALD secretion was shown among the subgroup of patients with acromegaly tested with MSI. CONCLUSIONS This study provides evidence of an increased prevalence of anatomic and functional adrenal alterations in patients with acromegaly; further studies will clarify the importance of evaluating these subjects with baseline hormonal investigation along with dynamic testing and modified cut-offs.
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Affiliation(s)
- Theodora Pappa
- Department of Endocrinology and Diabetes Center, Athens General Hospital G. Gennimatas, Athens, Greece
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