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Xu C. Extra-adrenal aldosterone: a mini review focusing on the physiology and pathophysiology of intrarenal aldosterone. Endocrine 2024; 83:285-301. [PMID: 37847370 DOI: 10.1007/s12020-023-03566-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 10/08/2023] [Indexed: 10/18/2023]
Abstract
PURPOSE Accumulating evidence has demonstrated the existence of extra-adrenal aldosterone in various tissues, including the brain, heart, vascular, adipocyte, and kidney, mainly based on the detection of the CYP11B2 (aldosterone synthase, cytochrome P450, family 11, subfamily B, polypeptide 2) expression using semi-quantitative methods including reverse transcription-polymerase chain reaction and antibody-based western blotting, as well as local tissue aldosterone levels by antibody-based immunosorbent assays. This mini-review highlights the current evidence and challenges in extra-adrenal aldosterone, focusing on intrarenal aldosterone. METHODS A narrative review. RESULTS Locally synthesized aldosterone may play a vital role in various physio-pathological processes, especially cardiovascular events. The site of local aldosterone synthesis in the kidney may include the mesangial cells, podocytes, proximal tubules, and collecting ducts. The synthesis of renal aldosterone may be regulated by (pro)renin receptor/(pro)renin, angiotensin II/Angiotensin II type 1 receptor, wnt/β-catenin, cyclooxygenase-2/prostaglandin E2, and klotho. Enhanced renal aldosterone release promotes Na+ reabsorption and K+ excretion in the distal nephron and may contribute to the progress of diabetic nephropathy and salt-related hypertension. CONCLUSIONS Inhibition of intrarenal aldosterone signaling by aldosterone synthase inhibitors or mineralocorticoid receptor antagonists may be a hopeful pharmacological technique for the therapy of diabetic nephropathy and saltrelated hypertension. Yet, current reports are often conflicting or ambiguous, leading many to question whether extra-adrenal aldosterone exists, or whether it is of any physiological and pathophysiological significance.
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Affiliation(s)
- Chuanming Xu
- Translational Medicine Centre, Jiangxi University of Chinese Medicine, Nanchang, 330002, Jiangxi, China.
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2
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Leaves of Cedrela sinensis Attenuate Chronic Unpredictable Mild Stress-Induced Depression-like Behavior via Regulation of Hormonal and Inflammatory Imbalance. Antioxidants (Basel) 2022; 11:antiox11122448. [PMID: 36552656 PMCID: PMC9774296 DOI: 10.3390/antiox11122448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/08/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022] Open
Abstract
This study aimed to evaluate the protective effects of ethyl acetate fraction from Cedrela sinensis (EFCS) against chronic unpredictable mild stress (CUMS)-induced behavioral dysfunction and stress response in C57BL/6 mice. The physiological compounds of EFCS were identified as rutin, isoquercitrin, ethyl gallate, quercitrin, kaempferol-3-O-rhamnoside, and ethyl digallate, using UPLC-Q-TOF/MSE. To evaluate the neuroprotective effect of EFCS, H2O2- and corticosterone-induced neuronal cell viability was conducted in human neuroblastoma MC-IXC cells. It was found that EFCS alleviated depression-like behavior by conducting the sucrose preference test (SPT), forced swimming test (FST), open field test (OFT), and tail suspension test (TST). EFCS inhibited mitochondrial dysfunction related to neuronal energy metabolism by regulating reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP), and ATP contents in brain tissue. In addition, the administration of EFCS regulated the stress hormones in serum. EFCS regulated stress-related indicators such as CRF, ACTH, CYP11B1, and BDNF. Moreover, EFCS downregulated the inflammatory responses and apoptosis proteins such as caspase-1, TNF-α, IL-1β, p-JNK, BAX, and p-tau in brain tissues. These results suggest that EFCS might be a potential natural plant material that alleviates CUMS-induced behavior disorder by regulating inflammation in brain tissue against CUMS-induced depression.
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3
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Lansdell TA, Dorrance AM. Chronic cerebral hypoperfusion in male rats results in sustained HPA activation and hyperinsulinemia. Am J Physiol Endocrinol Metab 2022; 322:E24-E33. [PMID: 34747203 PMCID: PMC8721904 DOI: 10.1152/ajpendo.00233.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Vascular contributions to cognitive impairment and dementia (VCID) is a spectrum of cognitive deficits caused by cerebrovascular disease, for which insulin resistance is a major risk factor. A major cause of VCID is chronic cerebral hypoperfusion (CCH). Under stress, sustained hypothalamic-pituitary-adrenal axis (HPA) activation can result in insulin resistance. Little is known about the effects of CCH on the HPA axis. We hypothesized that CCH causes sustained HPA activation and insulin resistance. Male rats were subjected to bilateral carotid artery stenosis (BCAS) for 12 wk to induce CCH and VCID. BCAS reduced cerebral blood flow and caused memory impairment. Plasma adrenocorticotropic hormone was increased in the BCAS rats (117.2 ± 9.6 vs. 88.29 ± 9.1 pg/mL, BCAS vs. sham, P = 0.0236), as was corticosterone (220 ± 21 vs. 146 ± 18 ng/g feces, BCAS vs. sham, P = 0.0083). BCAS rats were hypoglycemic (68.1 ± 6.1 vs. 76.5 ± 5.9 mg/dL, BCAS vs. sham, P = 0.0072), with increased fasting insulin (481.6 ± 242.6 vs. 97.94 ± 40.02 pmol/L, BCAS vs. sham, P = 0.0003) indicating that BCAS rats were insulin resistant [homeostasis model assessment of β-cell function-insulin resistance (HOMA-IR): 11.71 ± 6.47 vs. 2.62 ± 0.93; BCAS vs. control, P = 0.0008]. Glucose tolerance tests revealed that BCAS rats had lower blood glucose areas under the curve (AUCs) than controls (250 ± 12 vs. 326 ± 20 mg/dL/h, BCAS vs. sham, P = 0.0075). These studies indicate that CCH causes sustained activation of the HPA and results in insulin resistance, a condition that is expected to worsen VCID.NEW & NOTEWORTHY Cerebrovascular disease and insulin resistance are two major risk factors for the development of dementia. Here, we demonstrate that chronic cerebral hypoperfusion results in glucocorticoid excess and hyperinsulinemia. This study indicates that chronic cerebral hypoperfusion, glucocorticoid excess, and insulin resistance participate in a detrimental cycle that could exacerbate cerebral vascular disease and dementia.
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Affiliation(s)
- Theresa A Lansdell
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan
| | - Anne M Dorrance
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan
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4
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Salehzadeh M, Soma KK. Glucocorticoid production in the thymus and brain: Immunosteroids and neurosteroids. Brain Behav Immun Health 2021; 18:100352. [PMID: 34988497 PMCID: PMC8710407 DOI: 10.1016/j.bbih.2021.100352] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 09/05/2021] [Accepted: 09/17/2021] [Indexed: 12/23/2022] Open
Abstract
Glucocorticoids (GCs) regulate a myriad of physiological systems, such as the immune and nervous systems. Systemic GC levels in blood are often measured as an indicator of local GC levels in target organs. However, several extra-adrenal organs can produce and metabolize GCs locally. More sensitive and specific methods for GC analysis (i.e., mass spectrometry) allow measurement of local GC levels in small tissue samples with low GC concentrations. Consequently, is it now apparent that systemic GC levels often do not reflect local GC levels. Here, we review the use of systemic GC measurements in clinical and research settings, discuss instances where systemic GC levels do not reflect local GC levels, and present evidence that local GC levels provide useful insights, with a focus on local GC production in the thymus (immunosteroids) and brain (neurosteroids). Lastly, we suggest key areas for further research, such as the roles of immunosteroids and neurosteroids in neonatal programming and the potential clinical relevance of local GC modulators.
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Affiliation(s)
- Melody Salehzadeh
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Kiran K Soma
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
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5
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Yang H, Tan H, Huang H, Li J. Advances in Research on the Cardiovascular Complications of Acromegaly. Front Oncol 2021; 11:640999. [PMID: 33869029 PMCID: PMC8050332 DOI: 10.3389/fonc.2021.640999] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 03/16/2021] [Indexed: 02/05/2023] Open
Abstract
Cardiovascular-related complications are one of the most common complications in patients with acromegaly, and can lead to an increased risk of death. Hypertension and cardiomyopathy are the main cardiovascular complications. The characteristics of acromegalic cardiomyopathy are concentric biventricular hypertrophy and diastolic dysfunction. In addition, arrhythmia and heart valve disease are common cardiac complications in acromegaly. Although the underlying pathophysiology has not been fully elucidated, the spontaneous overproduction of GH and IGF-1, increasing age, prolonged duration of disease and the coexistence of other cardiovascular risk factors are crucial to cardiac complications in patients with acromegaly. Early diagnosis and appropriate treatment of acromegaly might be beneficial for the prevention of cardiomyopathy and premature death.
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Affiliation(s)
- Han Yang
- Department of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu, China.,Department of Endocrinology and Metabolism, Chongqing Sixth People's Hospital, Chongqing, China
| | - Huiwen Tan
- Department of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu, China
| | - He Huang
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China
| | - Jianwei Li
- Department of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu, China
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Hamden JE, Gray KM, Salehzadeh M, Kachkovski GV, Forys BJ, Ma C, Austin SH, Soma KK. Steroid profiling of glucocorticoids in microdissected mouse brain across development. Dev Neurobiol 2021; 81:189-206. [PMID: 33420760 DOI: 10.1002/dneu.22808] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 12/28/2020] [Accepted: 12/29/2020] [Indexed: 12/15/2022]
Abstract
Corticosterone is produced by the adrenal glands and also produced locally by other organs, such as the brain. Local levels of corticosterone in specific brain regions during development are not known. Here, we microdissected brain tissue and developed a novel liquid chromatography tandem mass spectrometry method (LC-MS/MS) to measure a panel of seven steroids (including 11-deoxycorticosterone (DOC), corticosterone, and 11-dehydrocorticosterone (DHC) in the blood, hippocampus (HPC), cerebral cortex (CC), and hypothalamus (HYP) of mice at postnatal day (PND) 5, 21, and 90. In a second cohort of mice, we measured the expression of three genes that code for steroidogenic enzymes that regulate corticosterone levels (Cyp11b1, Hsd11b1, and Hsd11b2) in the HPC, CC, and HYP. There were region-specific patterns of steroid levels across development, including higher corticosterone levels in the HPC and HYP than in the blood at PND5. In contrast, corticosterone levels were higher in the blood than in all brain regions at PND21 and PND90. Brain corticosterone levels were not positively correlated with blood corticosterone levels, and correlations across brain regions increased with age. Local corticosterone levels were best predicted by local DOC levels at PND5, but by local DHC levels at PND21 and PND90. Transcripts for the three enzymes were detectable in all samples (with highest expression of Hsd11b1) and showed region-specific changes with age. These data demonstrate that individual brain regions fine-tune local levels of corticosterone during early development and that coupling of glucocorticoid levels across regions increases with age.
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Affiliation(s)
- Jordan E Hamden
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Katherine M Gray
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - Melody Salehzadeh
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - George V Kachkovski
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Brandon J Forys
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - Chunqi Ma
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - Suzanne H Austin
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, USA
| | - Kiran K Soma
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Department of Psychology, University of British Columbia, Vancouver, BC, Canada.,Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
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7
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Sarin H. Pressure regulated basis for gene transcription by delta-cell micro-compliance modeled in silico: Biphenyl, bisphenol and small molecule ligand models of cell contraction-expansion. PLoS One 2020; 15:e0236446. [PMID: 33021979 PMCID: PMC7537880 DOI: 10.1371/journal.pone.0236446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/06/2020] [Indexed: 12/19/2022] Open
Abstract
Molecular diameter, lipophilicity and hydrophilicity exclusion affinity limits exist for small molecule carrier-mediated diffusion or transport through channel pores or interaction with the cell surface glycocalyx. The molecular structure lipophilicity limit for non-specific carrier-mediated transmembrane diffusion through polarity-selective transport channels of the cell membrane is Lexternal structure ∙ Hpolar group-1 of ≥ 1.07. The cell membrane channel pore size is > 0.752 and < 0.758 nm based on a 3-D ellipsoid model (biphenyl), and within the molecular diameter size range 0.744 and 0.762 nm based on a 2-D elliptical model (alkanol). The adjusted van der Waals diameter (vdWD, adj; nm) for the subset of halogenated vapors is predictive of the required MAC for anesthetic potency at an initial (-) Δ Cmicro effect. The molecular structure L ∙ Hpolar group-1 for Neu5Ac is 0.080, and the L ∙ Hpolar group-1 interval range for the cell surface glycocalyx hydrophilicity barrier interaction is 0.101 (Saxitoxin, Stx; Linternal structure ∙ Hpolar group-1) - 0.092 (m-xylenediamine, Lexternal structure · Hpolar group). Differential predictive effective pressure mapping of gene activation or repression reveals that p-dioxin exposure results in activation of AhR-Erβ (Arnt)/Nrf-2, Pparδ, Errγ (LxRα), Dio3 (Dio2) and Trα limbs, and due to high affinity Dio2 and Dio3 (OH-TriCDD, Lext · H-1: 1.91–4.31) exothermy-antagonism (Δ contraction) with high affinity T4/rT3-TRα-mediated agonism (Δ expansion). co-planar PCB metabolite exposure (Lext · H-1: 1.95–3.91) results in activation of AhR (Erα/β)/Nrf2, Rev-Erbβ, Errα, Dio3 (Dio2) and Trα limbs with a Δ Cmicro contraction of 0.89 and Δ Cmicro expansion of 1.05 as compared to p-dioxin. co-, ortho-planar PCB metabolite exposure results in activation of Car/PxR, Pparα (Srebf1,—Lxrβ), Arnt (AhR-Erβ), AR, Dio1 (Dio2) and Trβ limbs with a Δ Cmicro contraction of 0.73 and Δ Cmicro expansion of 1.18 (as compared to p-dioxin). Bisphenol A exposure (Lext struct ∙ H-1: 1.08–1.12, BPA–BPE, Errγ; BPAF, Lext struct ∙ H-1: 1.23, CM Erα, β) results in increased duration at Peff for Timm8b (Peff 0.247) transcription and in indirect activation of the AhR/Nrf-2 hybrid pathway with decreased duration at Peff 0.200 (Nrf1) and increased duration at Peff 0.257 (Dffa). The Bpa/Bpaf convergent pathway Cmicro contraction-expansion response increase in the lower Peff interval is 0.040; in comparison, small molecule hormone Δ Cmicro contraction-expansion response increases in the lower Peff intervals for gene expression ≤ 0.168 (Dex· GR) ≥ 0.156 (Dht · AR), with grade of duration at Peff (min·count) of 1.33x105 (Dex/Cort) and 1.8–2.53x105 (Dht/R1881) as compared to the (-) coupled (+) Δ CmicroPeff to 0.136 (Wnt5a, Esr2) with applied DES (1.86x106). The subtype of trans-differentiated cell as a result of an applied toxin or toxicant is predictable by delta-Cmicro determined by Peff mapping. Study findings offer additional perspective on the basis for pressure regulated gene transcription by alterations in cell micro-compliance (Δ contraction-expansion, Cmicro), and are applicable for the further predictive modeling of gene to gene transcription interactions, and small molecule modulation of cell effective pressure (Peff) and its potential.
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Affiliation(s)
- Hemant Sarin
- Freelance Investigator in Translational Science and Medicine, Charleston, West Virginia, United States of America
- * E-mail:
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8
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Chambers L, Dorrance AM. Regulation of ion channels in the microcirculation by mineralocorticoid receptor activation. CURRENT TOPICS IN MEMBRANES 2020; 85:151-185. [PMID: 32402638 DOI: 10.1016/bs.ctm.2020.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The mineralocorticoid receptor (MR) has classically been studied in the renal epithelium for its role in regulating sodium and water balance and, subsequently, blood pressure. However, the MR also plays a critical role in the microvasculature by regulating ion channel expression and function. Activation of the MR by its endogenous agonist aldosterone results in translocation of the MR into the nucleus, where it can act as a transcription factor. Although most of the actions of the aldosterone can be attributed to its genomic activity though MR activation, it can also act by nongenomic mechanisms. Activation of this ubiquitous receptor increases the expression of epithelial sodium channels (ENaC) in both the endothelium and smooth muscle cells of peripheral and cerebral vessels. MR activation also regulates activity of calcium channels, calcium-activated potassium channels, and various transient receptor potential (TRP) channels. Modification of these ion channels results in a myriad of negative consequences, including impaired endothelium-dependent vasodilation, alterations in generation of myogenic tone, and increased inflammation and oxidative stress. Taken together, these studies demonstrate the importance of studying the impact of the MR on ion channel function in the vasculature. While research in this area has made advances in recent years, there are still many large gaps in knowledge that need to be filled. Crucial future directions of study include defining the molecular mechanisms involved in this interaction, as well as elucidating the potential sex differences that may exist, as these areas of understanding are currently lacking.
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Affiliation(s)
- Laura Chambers
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States
| | - Anne M Dorrance
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States.
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9
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Leenen FHH, Wang HW, Hamlyn JM. Sodium pumps, ouabain and aldosterone in the brain: A neuromodulatory pathway underlying salt-sensitive hypertension and heart failure. Cell Calcium 2019; 86:102151. [PMID: 31954234 DOI: 10.1016/j.ceca.2019.102151] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 12/15/2019] [Indexed: 02/08/2023]
Abstract
Accumulating evidence obtained over the last three decades has revealed a neuroendocrine system in the brain that mediates long term increases in blood pressure. The system involves distinct ion transport pathways including the alpha-2 isoform of the Na,K pump and epithelial sodium channels, as well as critical hormone elements such as angiotensin II, aldosterone, mineralocorticoid receptors and endogenous ouabain. Activation of this system either by circulating or central sodium ions and/or angiotensin II leads to a cascading sequence of events that begins in the hypothalamus and involves the participation of several brain nuclei including the subfornical organ, supraoptic and paraventricular nuclei and the rostral ventral medulla. Key events include heightened aldosterone synthesis and mineralocorticoid receptor activation, upregulation of epithelial sodium channels, augmented synthesis and secretion of endogenous ouabain from hypothalamic magnocellular neurons, and sustained increases in sympathetic outflow. The latter step depends upon increased production of angiotensin II and the primary amplification of angiotensin II type I receptor signaling from the paraventricular nucleus to the rostral ventral lateral medulla. The transmission of sympathetic traffic is secondarily amplified in the periphery by increased short- and long-term potentiation in sympathetic ganglia and by sustained actions of endogenous ouabain in the vascular wall that augment expression of sodium calcium exchange, increase cytosolic Ca2+ and heighten myogenic tone and contractility. Upregulation of this multi-amplifier system participates in forms of hypertension where salt, angiotensin and/or aldosterone are elevated and contributes to adverse outcomes in heart failure.
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Affiliation(s)
- Frans H H Leenen
- Brain and Heart Research Group, University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - Hong-Wei Wang
- Brain and Heart Research Group, University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - John M Hamlyn
- Department of Physiology, University of Maryland, Baltimore, MD, USA.
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Yasuda A, Seki T, Kametani Y, Koizumi M, Kitajima N, Oki M, Seki M, Kakuta T, Fukagawa M. Glucocorticoid Receptor Antagonist Administration Prevents Adrenal Gland Atrophy in an ACTH-Independent Cushing's Syndrome Rat Model. Int J Endocrinol 2019; 2019:8708401. [PMID: 30915117 PMCID: PMC6399522 DOI: 10.1155/2019/8708401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 01/06/2019] [Indexed: 11/17/2022] Open
Abstract
ACTH-independent Cushing's syndrome (CS) is mainly caused by cortisol-secreting adrenocortical tumours. It is well known that secondary adrenal insufficiency occurs after surgical resection of these tumours. In this regard, impaired adrenocortical function is likely induced by atrophy of the residual adrenal tissue as a result of chronic suppression by the low ACTH levels of the hypercortisolism state. Therefore, we considered the prevention of adrenal atrophy as a method for preventing postoperative adrenal insufficiency. On the basis of these findings, we hypothesized that the use of a glucocorticoid receptor (GR) antagonist before surgery in ACTH-independent CS would rapidly activate the hypothalamic-pituitary-adrenal (HPA) axis and residual adrenal function. We thus examined adrenal function in a dexamethasone- (DEX-) induced CS rat model with or without mifepristone (MIF). In this study, MIF-treated rats had elevated plasma ACTH levels and increased adrenal weights. In addition, we confirmed that there were fewer atrophic changes, as measured by the pathological findings and mRNA expression levels of corticosterone synthase CYP11B1 in the adrenal glands, in MIF-treated rats. These results indicate that MIF treatment prevents the suppression of the HPA axis and the atrophy of the residual adrenal tissue. Therefore, our study suggests that preoperative GR antagonist administration may improve residual adrenal function and prevent postoperative adrenal insufficiency in ACTH-independent CS.
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Affiliation(s)
- Atsushi Yasuda
- Division of Nephrology, Endocrinology and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Toshiro Seki
- Division of Nephrology, Endocrinology and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Yoshie Kametani
- Department of Molecular Life Science, Division of Basic Medical Science, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Masahiro Koizumi
- Division of Nephrology, Endocrinology and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Natsumi Kitajima
- Division of Nephrology, Endocrinology and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Masayuki Oki
- Division of General Internal Medicine, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Masami Seki
- Seirei Numazu Hospital, Shizuoka 410-8555, Japan
| | - Takatoshi Kakuta
- Division of Nephrology, Endocrinology and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Masafumi Fukagawa
- Division of Nephrology, Endocrinology and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa 259-1193, Japan
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11
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Abruzzese GA, Crisosto N, De Grava Kempinas W, Sotomayor-Zárate R. Developmental programming of the female neuroendocrine system by steroids. J Neuroendocrinol 2018; 30:e12632. [PMID: 29968423 DOI: 10.1111/jne.12632] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 06/03/2018] [Accepted: 07/01/2018] [Indexed: 12/30/2022]
Abstract
Developmental programming refers to processes that occur during early life that may have long-term consequences, modulating adult health and disease. Complex diseases, such as diabetes, cancer and cardiovascular disease, have a high prevalence in different populations, are multifactorial, and may have a strong environmental component. The environment interacts with organisms, affecting their behaviour, morphology and physiology. This interaction may induce permanent or long-term changes, and organisms may be more susceptible to environmental factors during certain developmental stages, such as the prenatal and early postnatal periods. Several factors have been identified as responsible for inducing the reprogramming of various reproductive and nonreproductive tissues. Among them, both natural and synthetic steroids, such as endocrine disruptors, are known to have either detrimental or positive effects on organisms depending on the dose of exposure, stage of development and biological sexual background. The present review focuses on the action of steroids and endocrine disruptors as agents involved in developmental programming and on their modulation and effects on female neuroendocrine functions.
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Affiliation(s)
- Giselle Adriana Abruzzese
- Laboratorio de Fisio-patología Ovárica, Centro de Estudios Farmacológicos y Botánicos (CEFYBO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Nicolás Crisosto
- Endocrinology and Metabolism Laboratory West Division, School of Medicine, University of Chile, Santiago, Chile
- Endocrinology Unit, Clínica Las Condes, Santiago, Chile
| | - Wilma De Grava Kempinas
- Laboratory of Reproductive and Developmental Biology and Toxicology, Department of Morphology, Institute of Biosciences, Universidade Estadual Paulista-UNESP, Botucatu, Sao Paulo, Brazil
| | - Ramón Sotomayor-Zárate
- Laboratorio de Neuroquímica y Neurofarmacología, Centro de Neurobiología y Fisiopatología Integrativa, Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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Colmers PLW, Bains JS. Balancing tonic and phasic inhibition in hypothalamic corticotropin-releasing hormone neurons. J Physiol 2018; 596:1919-1929. [PMID: 29419884 DOI: 10.1113/jp275588] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 01/29/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS GABA transporter (GAT) blockade recruits extrasynaptic GABAA receptors (GABAA Rs) and amplifies constitutive presynaptic GABAB R activity. Extrasynaptic GABAA Rs contribute to a tonic current. Corticosteroids increase the tonic current mediated by extrasynaptic GABAA Rs. ABSTRACT Corticotropin-releasing hormone (CRH) neurons in the paraventricular nucleus of the hypothalamus (PVN) are integratory hubs that regulate the endocrine response to stress. GABA inputs provide a basal inhibitory tone that constrains this system and circulating glucocorticoids (CORT) are important feedback controllers of CRH output. Surprisingly little is known about the direct effects of CORT on GABA synapses in PVN. Here we used whole-cell patch clamp recordings from CRH neurons in mouse hypothalamic brain slices to examine the effects of CORT on synaptic and extrasynaptic GABA signalling. We show that GABA transporters (GATs) limit constitutive activation of presynaptic GABAB receptors and ensure high release probability at GABA synapses. GATs in combination with GABAB receptors also curtail extrasynaptic GABAA R signalling. CORT has no effect on synaptic GABA signalling, but increases extrasynaptic GABA tone through upregulation of postsynaptic GABAA receptors. These data show that efficient GABA clearance and autoinhibition control the balance between synaptic (phasic) and extrasynaptic (tonic) inhibition in PVN CRH neurons. This balance is shifted towards increased extrasynaptic inhibition by CORT.
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Affiliation(s)
- Phillip L W Colmers
- Hotchkiss Brain Institute and the Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Jaideep S Bains
- Hotchkiss Brain Institute and the Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
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13
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Menzies RI, Zhao X, Mullins LJ, Mullins JJ, Cairns C, Wrobel N, Dunbar DR, Bailey MA, Kenyon CJ. Transcription controls growth, cell kinetics and cholesterol supply to sustain ACTH responses. Endocr Connect 2017; 6:446-457. [PMID: 28720595 PMCID: PMC5574282 DOI: 10.1530/ec-17-0092] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 07/18/2017] [Indexed: 01/29/2023]
Abstract
Chronic ACTH exposure is associated with adrenal hypertrophy and steroidogenesis. The underlying molecular processes in mice have been analysed by microarray, histological and immunohistochemical techniques. Synacthen infused for 2 weeks markedly increased adrenal mass and plasma corticosterone levels. Microarray analysis found greater than 2-fold changes in expression of 928 genes (P < 0.001; 397 up, 531 down). These clustered in pathways involved in signalling, sterol/lipid metabolism, cell proliferation/hypertrophy and apoptosis. Signalling genes included some implicated in adrenal adenomas but also upregulated genes associated with cyclic AMP and downregulated genes associated with aldosterone synthesis. Sterol metabolism genes were those promoting cholesterol supply (Scarb1, Sqle, Apoa1) and disposal (Cyp27a1, Cyp7b1). Oil red O staining showed lipid depletion consistent with reduced expression of genes involved in lipid synthesis. Genes involved in steroidogenesis (Star, Cyp11a1, Cyp11b1) were modestly affected (P < 0.05; <1.3-fold). Increased Ki67, Ccna2, Ccnb2 and Tk1 expression complemented immunohistochemical evidence of a 3-fold change in cell proliferation. Growth arrest genes, Cdkn1a and Cdkn1c, which are known to be active in hypertrophied cells, were increased >4-fold and cross-sectional area of fasciculata cells was 2-fold greater. In contrast, genes associated with apoptosis (eg Casp12, Clu,) were downregulated and apoptotic cells (Tunel staining) were fewer (P < 0.001) and more widely distributed throughout the cortex. In summary, long-term steroidogenesis with ACTH excess is sustained by genes controlling cholesterol supply and adrenal mass. ACTH effects on adrenal morphology and genes controlling cell hypertrophy, proliferation and apoptosis suggest the involvement of different cell types and separate molecular pathways.
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Affiliation(s)
- Robert I Menzies
- The University/BHF Centre for Cardiovascular ScienceUniversity of Edinburgh, The Queen's Medical Research Institute, Edinburgh, UK
| | - Xin Zhao
- The University/BHF Centre for Cardiovascular ScienceUniversity of Edinburgh, The Queen's Medical Research Institute, Edinburgh, UK
| | - Linda J Mullins
- The University/BHF Centre for Cardiovascular ScienceUniversity of Edinburgh, The Queen's Medical Research Institute, Edinburgh, UK
| | - John J Mullins
- The University/BHF Centre for Cardiovascular ScienceUniversity of Edinburgh, The Queen's Medical Research Institute, Edinburgh, UK
| | - Carolynn Cairns
- The University/BHF Centre for Cardiovascular ScienceUniversity of Edinburgh, The Queen's Medical Research Institute, Edinburgh, UK
| | - Nicola Wrobel
- The University/BHF Centre for Cardiovascular ScienceUniversity of Edinburgh, The Queen's Medical Research Institute, Edinburgh, UK
| | - Donald R Dunbar
- The University/BHF Centre for Cardiovascular ScienceUniversity of Edinburgh, The Queen's Medical Research Institute, Edinburgh, UK
| | - Matthew A Bailey
- The University/BHF Centre for Cardiovascular ScienceUniversity of Edinburgh, The Queen's Medical Research Institute, Edinburgh, UK
| | - Christopher J Kenyon
- The University/BHF Centre for Cardiovascular ScienceUniversity of Edinburgh, The Queen's Medical Research Institute, Edinburgh, UK
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14
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Keller CM, Breaux KN, Goeders NE. Effects of the combination of metyrapone and oxazepam on cocaine-induced increases in corticosterone in the medial prefrontal cortex and nucleus accumbens. Psychoneuroendocrinology 2017; 77:75-83. [PMID: 28024272 DOI: 10.1016/j.psyneuen.2016.12.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 12/05/2016] [Accepted: 12/05/2016] [Indexed: 10/20/2022]
Abstract
We have previously demonstrated that a combination of drugs (i.e., metyrapone and oxazepam) known to attenuate HPA-axis activity effectively decreases cocaine self-administration and cue reactivity in rats. However, we did not find changes in plasma corticosterone that matched the behavioral effects we observed, indicating that a different mechanism of action must be involved. Therefore, we hypothesized that the combination of metyrapone and oxazepam attenuates cocaine taking and seeking by decreasing cocaine-induced increases in corticosterone in the brain. Male rats were implanted with guide cannulae targeting the medial prefrontal cortex or nucleus accumbens. After the rats recovered from surgery, the microdialysis session was conducted. Rats were housed in the experimental chamber and the dialysis probes inserted into the guide cannulae the night before the session. The following day, dialysate samples were collected over a five-hour session. Baseline samples were collected for the first two hours, every 20min. Samples were then collected following administration of cocaine (15mg/kg, ip). Before injections of cocaine, rats were pretreated with either vehicle or the combination of metyrapone (50mg/kg, ip) and oxazepam (10mg/kg, ip). The administration of cocaine resulted in an increase in corticosterone in the medial prefrontal cortex following vehicle pretreatment, which was not observed in the nucleus accumbens. This cocaine-induced increase in corticosterone was attenuated by metyrapone/oxazepam. Reducing cocaine-induced increases in corticosterone in the medial prefrontal cortex might represent a novel mechanism through which the combination of metyrapone/oxazepam produces its behavioral effects.
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Affiliation(s)
- Courtney M Keller
- Department of Pharmacology, Toxicology & Neuroscience, LSU Health Sciences Center, Shreveport, LA 71130, United States.
| | - Kelly N Breaux
- Department of Pharmacology, Toxicology & Neuroscience, LSU Health Sciences Center, Shreveport, LA 71130, United States
| | - Nicholas E Goeders
- Department of Pharmacology, Toxicology & Neuroscience, LSU Health Sciences Center, Shreveport, LA 71130, United States
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15
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Evans LC, Ivy JR, Wyrwoll C, McNairn JA, Menzies RI, Christensen TH, Al-Dujaili EAS, Kenyon CJ, Mullins JJ, Seckl JR, Holmes MC, Bailey MA. Conditional Deletion of Hsd11b2 in the Brain Causes Salt Appetite and Hypertension. Circulation 2016; 133:1360-70. [PMID: 26951843 PMCID: PMC4819772 DOI: 10.1161/circulationaha.115.019341] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 02/12/2016] [Indexed: 11/30/2022]
Abstract
Supplemental Digital Content is available in the text. Background— The hypertensive syndrome of Apparent Mineralocorticoid Excess is caused by loss-of-function mutations in the gene encoding 11β-hydroxysteroid dehydrogenase type 2 (11βHSD2), allowing inappropriate activation of the mineralocorticoid receptor by endogenous glucocorticoid. Hypertension is attributed to sodium retention in the distal nephron, but 11βHSD2 is also expressed in the brain. However, the central contribution to Apparent Mineralocorticoid Excess and other hypertensive states is often overlooked and is unresolved. We therefore used a Cre-Lox strategy to generate 11βHSD2 brain-specific knockout (Hsd11b2.BKO) mice, measuring blood pressure and salt appetite in adults. Methods and Results— Basal blood pressure, electrolytes, and circulating corticosteroids were unaffected in Hsd11b2.BKO mice. When offered saline to drink, Hsd11b2.BKO mice consumed 3 times more sodium than controls and became hypertensive. Salt appetite was inhibited by spironolactone. Control mice fed the same daily sodium intake remained normotensive, showing the intrinsic salt resistance of the background strain. Dexamethasone suppressed endogenous glucocorticoid and abolished the salt-induced blood pressure differential between genotypes. Salt sensitivity in Hsd11b2.BKO mice was not caused by impaired renal sodium excretion or volume expansion; pressor responses to phenylephrine were enhanced and baroreflexes impaired in these animals. Conclusions— Reduced 11βHSD2 activity in the brain does not intrinsically cause hypertension, but it promotes a hunger for salt and a transition from salt resistance to salt sensitivity. Our data suggest that 11βHSD2-positive neurons integrate salt appetite and the blood pressure response to dietary sodium through a mineralocorticoid receptor–dependent pathway. Therefore, central mineralocorticoid receptor antagonism could increase compliance to low-sodium regimens and help blood pressure management in cardiovascular disease.
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Affiliation(s)
- Louise C Evans
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Jessica R Ivy
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Caitlin Wyrwoll
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Julie A McNairn
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Robert I Menzies
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Thorbjørn H Christensen
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Emad A S Al-Dujaili
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Christopher J Kenyon
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - John J Mullins
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Jonathan R Seckl
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Megan C Holmes
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Matthew A Bailey
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense.
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16
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Central nervous system circuits modified in heart failure: pathophysiology and therapeutic implications. Heart Fail Rev 2015; 19:759-79. [PMID: 24573960 DOI: 10.1007/s10741-014-9427-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The pathophysiology of heart failure (HF) is characterized by an abnormal activation of neurohumoral systems, including the sympathetic nervous and the renin-angiotensin-aldosterone systems, which have long-term deleterious effects on the disease progression. Perpetuation of this neurohumoral activation is partially dependent of central nervous system (CNS) pathways, mainly involving the paraventricular nucleus of the hypothalamus and some regions of the brainstem. Modifications in these integrative CNS circuits result in the attenuation of sympathoinhibitory and exacerbation of sympathoexcitatory pathways. In addition to the regulation of sympathetic outflow, these central pathways coordinate a complex network of agents with an established pathophysiological relevance in HF such as angiotensin, aldosterone, and proinflammatory cytokines. Central pathways could be potential targets in HF therapy since the current mainstay of HF pharmacotherapy aims primarily at antagonizing the peripheral mechanisms. Thus, in the present review, we describe the role of CNS pathways in HF pathophysiology and as potential novel therapeutic targets.
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17
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Heimovics SA, Trainor BC, Soma KK. Rapid Effects of Estradiol on Aggression in Birds and Mice: The Fast and the Furious. Integr Comp Biol 2015; 55:281-93. [PMID: 25980562 DOI: 10.1093/icb/icv048] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Across invertebrates and vertebrates, steroids are potent signaling molecules that affect nearly every cell in the organism, including cells of the nervous system. Historically, researchers have focused on the genomic (or "nuclear-initiated") effects of steroids. However, all classes of steroids also have rapid non-genomic (or "membrane-initiated") effects, although there is far less basic knowledge of these non-genomic effects. In particular, steroids synthesized in the brain ("neurosteroids") have genomic and non-genomic effects on behavior. Here, we review evidence that estradiol has rapid effects on aggression, an important social behavior, and on intracellular signaling cascades in relevant regions of the brain. In particular, we focus on studies of song sparrows (Melospiza melodia) and Peromyscus mice, in which estradiol has rapid behavioral effects under short photoperiods only. Furthermore, in captive Peromyscus, estrogenic compounds (THF-diols) in corncob bedding profoundly alter the rapid effects of estradiol. Environmental factors in the laboratory, such as photoperiod, diet, and bedding, are critical variables to consider in experimental design. These studies are consistent with the hypothesis that locally-produced steroids are more likely than systemic steroids to act via non-genomic mechanisms. Furthermore, these studies illustrate the dynamic balance between genomic and non-genomic signaling for estradiol, which is likely to be relevant for other steroids, behaviors, and species.
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Affiliation(s)
- Sarah A Heimovics
- *Department of Biology, University of St Thomas, St Paul, MN 55105, USA;
| | - Brian C Trainor
- Department of Psychology, University of California-Davis, Davis, CA 95616, USA
| | - Kiran K Soma
- Departments of Psychology and Zoology, Graduate Program in Neuroscience, University of British Columbia, Vancouver, British Columbia, V6T 1Z7, Canada
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18
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Fokidis HB, Adomat HH, Kharmate G, Hosseini-Beheshti E, Guns ES, Soma KK. Regulation of local steroidogenesis in the brain and in prostate cancer: lessons learned from interdisciplinary collaboration. Front Neuroendocrinol 2015; 36:108-29. [PMID: 25223867 DOI: 10.1016/j.yfrne.2014.08.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 08/28/2014] [Accepted: 08/28/2014] [Indexed: 11/16/2022]
Abstract
Sex steroids play critical roles in the regulation of the brain and many other organs. Traditionally, researchers have focused on sex steroid signaling that involves travel from the gonads via the circulation to intracellular receptors in target tissues. This classic concept has been challenged, however, by the growing number of cases in which steroids are synthesized locally and act locally within diverse tissues. For example, the brain and prostate carcinoma were previously considered targets of gonadal sex steroids, but under certain circumstances, these tissues can upregulate their steroidogenic potential, particularly when circulating sex steroid concentrations are low. We review some of the similarities and differences between local sex steroid synthesis in the brain and prostate cancer. We also share five lessons that we have learned during the course of our interdisciplinary collaboration, which brought together neuroendocrinologists and cancer biologists. These lessons have important implications for future research in both fields.
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Affiliation(s)
- H Bobby Fokidis
- Department of Biology, Rollins College, Winter Park, FL 37289, USA; Department of Psychology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Vancouver Prostate Centre, Vancouver, BC V6H 3Z6, Canada.
| | - Hans H Adomat
- Vancouver Prostate Centre, Vancouver, BC V6H 3Z6, Canada
| | | | | | - Emma S Guns
- Vancouver Prostate Centre, Vancouver, BC V6H 3Z6, Canada; Department of Urological Sciences, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Kiran K Soma
- Department of Psychology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Brain Research Centre, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
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19
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Guerin GF, Schmoutz CD, Goeders NE. The extra-adrenal effects of metyrapone and oxazepam on ongoing cocaine self-administration. Brain Res 2014; 1575:45-54. [PMID: 24887642 DOI: 10.1016/j.brainres.2014.05.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 05/20/2014] [Accepted: 05/25/2014] [Indexed: 11/30/2022]
Abstract
Investigation of the role of stress in cocaine addiction has yielded an efficacious combination of metyrapone and oxazepam, hypothesized to decrease relapse to cocaine use by reducing stress-induced craving. However, recent data suggest an extra-adrenal role for metyrapone in mediating stress- and addiction-related behaviors. The interactions between the physiological stress response and cocaine self-administration were characterized in rodents utilizing surgical adrenalectomy and pharmacological treatment. Male Wistar rats were trained to self-administer cocaine (0.25mg/kg/infusion) and food pellets under a concurrent alternating fixed-ratio schedule of reinforcement. Surgical removal of the adrenal glands resulted in a significant decrease in plasma corticosterone and a consequent increase in ACTH, as expected. However, adrenalectomy did not significantly affect ongoing cocaine self-administration. Pretreatment with metyrapone, oxazepam and their combinations in intact rats resulted in a significant decrease in cocaine-reinforced responses. These same pharmacological treatments were still effective in reducing cocaine- and food-reinforced responding in adrenalectomized rats. The results of these experiments demonstrate that adrenally-derived steroids are not necessary to maintain cocaine-reinforced responding in cocaine-experienced rats. These results also demonstrate that metyrapone may produce effects outside of the adrenal gland, presumably in the central nervous system, to affect cocaine-related behaviors.
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Affiliation(s)
- Glenn F Guerin
- Department of Pharmacology, Toxicology, & Neuroscience, Louisiana State University Health Sciences Center, 1501 Kings Highway, Box 33932, Shreveport, LA 71130, USA
| | - Christopher D Schmoutz
- Department of Pharmacology, Toxicology, & Neuroscience, Louisiana State University Health Sciences Center, 1501 Kings Highway, Box 33932, Shreveport, LA 71130, USA.
| | - Nicholas E Goeders
- Department of Pharmacology, Toxicology, & Neuroscience, Louisiana State University Health Sciences Center, 1501 Kings Highway, Box 33932, Shreveport, LA 71130, USA
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Abstract
The role of sympathetic nerve activity in hypertension is currently receiving increased attention, because catheter-based renal denervation was recently shown to reduce blood pressure safely in patients with treatment-resistant hypertension. The central nervous system, which regulates sympathetic nerve activity and blood pressure, is pivotal. Central sympathoexcitation has been shown to be deeply involved in the pathogenesis of salt-sensitive hypertension, although its precise mechanisms have not yet been fully elucidated due to their complexity. Recently, a role for brain oxidative stress in sympathoexcitation has been suggested in some hypertensive animal models. We have demonstrated that increased brain oxidative stress may elevate arterial pressure through central sympathoexcitation in salt-sensitive hypertension. Several factors other than oxidative stress have also been shown to play important roles in central sympathetic activation. In the future, strategies may be developed to elicit a sympathetic inhibition by modulating these factors to prevent and manage salt-sensitive hypertension.
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Affiliation(s)
- Megumi Fujita
- Department of Nephrology and Endocrinology, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
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21
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Goeders NE, Guerin GF, Schmoutz CD. The combination of metyrapone and oxazepam for the treatment of cocaine and other drug addictions. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 69:419-79. [PMID: 24484984 DOI: 10.1016/b978-0-12-420118-7.00011-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Although scientists have been investigating the neurobiology of psychomotor stimulant reward for many decades, there is still no FDA-approved treatment for cocaine or methamphetamine abuse. Research in our laboratory has focused on the relationship between stress, the subsequent activation of the hypothalamic-pituitary-adrenal (HPA) axis, and psychomotor stimulant reinforcement for almost 30 years. This research has led to the development of a combination of low doses of the cortisol synthesis inhibitor, metyrapone, and the benzodiazepine, oxazepam, as a potential pharmacological treatment for cocaine and other substance use disorders. In fact, we have conducted a pilot clinical trial that demonstrated that this combination can reduce cocaine craving and cocaine use. Our initial hypothesis underlying this effect was that the combination of metyrapone and oxazepam reduced cocaine seeking and taking by decreasing activity within the HPA axis. Even so, doses of the metyrapone and oxazepam combination that consistently reduced cocaine taking and seeking did not reliably alter plasma corticosterone (or cortisol in the pilot clinical trial). Furthermore, subsequent research has demonstrated that this drug combination is effective in adrenalectomized rats, suggesting that these effects must be mediated above the level of the adrenal gland. Our evolving hypothesis is that the combination of metyrapone and oxazepam produces its effects by increasing the levels of neuroactive steroids, most notably tetrahydrodeoxycorticosterone, in the medial prefrontal cortex and amygdala. Additional research will be necessary to confirm this hypothesis and may lead to the development of improved and specific pharmacotherapies for the treatment of psychomotor stimulant use.
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Affiliation(s)
- Nicholas E Goeders
- Department of Pharmacology, Toxicology & Neuroscience, LSU Health Sciences Center, Shreveport, Louisiana, USA.
| | - Glenn F Guerin
- Department of Pharmacology, Toxicology & Neuroscience, LSU Health Sciences Center, Shreveport, Louisiana, USA
| | - Christopher D Schmoutz
- Department of Pharmacology, Toxicology & Neuroscience, LSU Health Sciences Center, Shreveport, Louisiana, USA
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22
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Lee KJ, Lee SY, Ji GE. Diabetes-ameliorating effects of fermented red ginseng and causal effects on hormonal interactions: testing the hypothesis by multiple group path analysis. J Med Food 2013; 16:383-95. [PMID: 23675990 DOI: 10.1089/jmf.2012.2583] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Although diagnostic criteria for metabolic syndrome (MtS) vary among various health professionals and organizations, blood glucose dysregulation and insulin resistance are common to all definitions. Red ginseng is beneficial for glucose regulation and insulin sensitivity but the mechanism is not yet elucidated. Ginsenosides Rh1 and Rg3 act as ligands of the estrogen receptor, and Rh2 and compound K act as ligands of the glucocorticoid receptors, which may influence the diabetes markers. The objective of this study was to test the hypothesis that there are significant causal relationships among diabetes-related markers and several hormones, and assess whether or not the consumption of fermented red ginseng (FRG) influences these causal relationships by multiple group path analysis and conventional statistical analyses. The 93 postmenopausal women were randomly divided into two groups for a double-blind trial. FRG powder and placebo were provided for 2 weeks. The data were analyzed by multiple group path analysis and the mean between groups were compared. The model's goodness of fit was excellent, with a root mean square error of approximation of 0.00, and comparative fit index of 1.00. The FRG group exhibited significantly increased levels of dehydroepiandrosterone sulfate (DHEAS), growth hormone (GH), and estradiol (E2), and they exhibited decreased levels of glycosylated hemoglobin (HbA1c), insulin, and homeostatic model assessment of insulin resistance. With regard to the hypothesis, the blood glucose lowering effects of FRG were due to the negative effects of aldosterone and increased GH, which was associated with DHEAS and E2. Even though the differences of variables between both groups were small, the total effects of these variables may indicate beneficial changes for the prevention of diabetes in healthy postmenopausal women.
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Affiliation(s)
- Kwang Jo Lee
- Department of Food and Nutrition, Research of Institute of Human Ecology, Seoul National University, Seoul, Korea
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23
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Cuffe JSM, O'Sullivan L, Simmons DG, Anderson ST, Moritz KM. Maternal corticosterone exposure in the mouse has sex-specific effects on placental growth and mRNA expression. Endocrinology 2012; 153:5500-11. [PMID: 22919064 DOI: 10.1210/en.2012-1479] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Maternal exposure to increased synthetic glucocorticoids (GC) during pregnancy is known to disturb fetal development and increase the risk of long-term disease. Maternal exposure to elevated levels of natural GC is likely to be common yet is relatively understudied. The placenta plays an important role in regulating fetal exposure to maternal GC but is itself vulnerable to maternal insults. This study uses a mouse model of maternal corticosterone (Cort) exposure to investigate its effects on the developing placenta. Mice were treated with Cort (33 μg/kg·h) for 60 h starting at embryonic d 12.5 (E12.5) before collection of placentas at E14.5 and E17.5. Although Cort exposure did not affect fetal size, placentas of male fetuses were larger at E17.5 in association with changes in placental Igf2. This increase in size was associated with an increase in placental thickness and an increase in placental junctional zone volume. Placentas from female fetuses were of normal size and had no changes in growth factor mRNA levels. The expression of the protective enzyme 11β-hydroxysteroid dehydrogenase type 2 was increased at E14.5 but was decreased in males at E17.5. In contrast, the expression of Nr3c1 (which encodes the GC receptor) was increased during the Cort exposure and remained elevated at E17.5 in the placentas of male fetuses. Our study has shown that maternal Cort exposure infers a sex-specific alteration to normal placental growth and growth factor expression, thus further adding to our understanding of the mechanisms of male dominance of programmed disease.
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Affiliation(s)
- J S M Cuffe
- School of Biomedical Sciences, The University of Queensland, St. Lucia, Australia
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24
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Xue B, Zhang Z, Roncari CF, Guo F, Johnson AK. Aldosterone acting through the central nervous system sensitizes angiotensin II-induced hypertension. Hypertension 2012; 60:1023-30. [PMID: 22949534 DOI: 10.1161/hypertensionaha.112.196576] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Previous studies have shown that preconditioning rats with a nonpressor dose of angiotensin II (Ang II) sensitizes the pressor response produced by later treatment with a higher dose of Ang II and that Ang II and aldosterone (Aldo) can modulate each other's pressor effects through actions involving the central nervous system. The current studies tested whether Aldo can cross-sensitize the pressor actions of Ang II to enhance hypertension by employing an induction-delay-expression experimental design. Male rats were implanted for telemetered blood pressure recording. During induction, subpressor doses of either subcutaneous or intracerebroventricular Aldo were delivered for 1 week. Rats were then rested for 1 week (delay) to assure that any exogenous Aldo was metabolized. After this, Ang II was given subcutaneously for 2 weeks (expression). During induction and delay, Aldo had no sustained effect on blood pressure. However, during expression, Ang II-induced hypertension was greater in the groups receiving subcutaneous or intracerebroventricular Aldo during induction in comparison with those groups receiving vehicle. Central administration of mineralocorticoid receptor antagonist blocked sensitization. Brain tissue collected at the end of delay and expression showed increased mRNA expression of several renin-angiotensin-aldosterone system components in cardiovascular-related forebrain regions of cross-sensitized rats. Cultured subfornical organ neurons preincubated with Aldo displayed greater increases in [Ca2+]i after Ang II treatment, and there was a greater Fra-like immunoreactivity present at the end of expression in cardiovascular-related forebrain structures. Taken together, these results indicate that Aldo pretreatment cross-sensitizes the development of Ang II-induced hypertension probably by mechanisms that involve the central nervous system.
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Affiliation(s)
- Baojian Xue
- Department of Psychology, Cardiovascular Center, University of Iowa, 11 Seashore Hall E, Iowa City, IA 52242, USA
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25
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Gomez-Sanchez EP, Gomez-Sanchez CE. Central regulation of blood pressure by the mineralocorticoid receptor. Mol Cell Endocrinol 2012; 350:289-98. [PMID: 21664417 PMCID: PMC3189429 DOI: 10.1016/j.mce.2011.05.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 05/19/2011] [Accepted: 05/22/2011] [Indexed: 12/30/2022]
Abstract
Addition of mineralocorticoid receptor (MR) antagonists to standard therapy for heart failure, kidney disease, metabolic syndrome, and diabetes is increasing steadily in response to clinical trials demonstrating clear benefits. In addition to blocking deleterious activity of MR within the heart, vessels and kidneys, MR antagonists target MR in hemodynamic regulatory centers in the brain, thereby decreasing excessive sympathetic nervous system drive, vasopressin release, abnormal baroreceptor function, and circulating and tissue pro-inflammatory cytokines. However, brain MR are also involved with cognition, memory, affect and functions yet to be determined. Understanding specific central mechanisms involved in blood pressure regulation by MR is necessary for the development of agents to target downstream events specific to central hemodynamic regulation, not only to avoid the hypokalemia caused by inhibition of renal tubular MR, but also to avoid untoward long term effects of inhibiting brain MR that are not involved in blood pressure control.
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Affiliation(s)
- Elise P Gomez-Sanchez
- Research Service, G.V. (Sonny) Montgomery VA Medical Center, 1500 Woodrow Wilson Dr., Jackson, MS 39216, USA.
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26
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MacKenzie SM, Connell JMC, Davies E. Non-adrenal synthesis of aldosterone: a reality check. Mol Cell Endocrinol 2012; 350:163-7. [PMID: 21767599 DOI: 10.1016/j.mce.2011.06.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 06/21/2011] [Accepted: 06/24/2011] [Indexed: 11/24/2022]
Abstract
Advances in the sensitivity of molecular techniques during the 1990s led to a flurry of studies that supported the existence of extra-adrenal sites of aldosterone production in various tissues including the brain and the heart. Subsequent work was often conflicting or ambiguous, leading many to question whether extra-adrenal aldosterone was of any physiological importance, or whether it even existed. In this article, we review these studies and, in light of this evidence, discuss whether the current lack of interest in extra-adrenal aldosterone biosynthesis is justified.
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Affiliation(s)
- Scott M MacKenzie
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
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27
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Wyrwoll CS, Holmes MC, Seckl JR. 11β-hydroxysteroid dehydrogenases and the brain: from zero to hero, a decade of progress. Front Neuroendocrinol 2011; 32:265-86. [PMID: 21144857 PMCID: PMC3149101 DOI: 10.1016/j.yfrne.2010.12.001] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 12/01/2010] [Accepted: 12/01/2010] [Indexed: 12/11/2022]
Abstract
Glucocorticoids have profound effects on brain development and adult CNS function. Excess or insufficient glucocorticoids cause myriad abnormalities from development to ageing. The actions of glucocorticoids within cells are determined not only by blood steroid levels and target cell receptor density, but also by intracellular metabolism by 11β-hydroxysteroid dehydrogenases (11β-HSD). 11β-HSD1 regenerates active glucocorticoids from their inactive 11-keto derivatives and is widely expressed throughout the adult CNS. Elevated hippocampal and neocortical 11β-HSD1 is observed with ageing and causes cognitive decline; its deficiency prevents the emergence of cognitive defects with age. Conversely, 11β-HSD2 is a dehydrogenase, inactivating glucocorticoids. The major central effects of 11β-HSD2 occur in development, as expression of 11β-HSD2 is high in fetal brain and placenta. Deficient feto-placental 11β-HSD2 results in a life-long phenotype of anxiety and cardiometabolic disorders, consistent with early life glucocorticoid programming.
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Affiliation(s)
- Caitlin S Wyrwoll
- Endocrinology Unit, Centre for Cardiovascular Science, Queen's Medical Research Institute, The University of Edinburgh, Edinburgh EH16 4TJ, UK.
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28
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Higo S, Hojo Y, Ishii H, Komatsuzaki Y, Ooishi Y, Murakami G, Mukai H, Yamazaki T, Nakahara D, Barron A, Kimoto T, Kawato S. Endogenous synthesis of corticosteroids in the hippocampus. PLoS One 2011; 6:e21631. [PMID: 21829438 PMCID: PMC3145636 DOI: 10.1371/journal.pone.0021631] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2011] [Accepted: 06/03/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Brain synthesis of steroids including sex-steroids is attracting much attention. The endogenous synthesis of corticosteroids in the hippocampus, however, has been doubted because of the inability to detect deoxycorticosterone (DOC) synthase, cytochrome P450(c21). METHODOLOGY/PRINCIPAL FINDINGS The expression of P450(c21) was demonstrated using mRNA analysis and immmunogold electron microscopic analysis in the adult male rat hippocampus. DOC production from progesterone (PROG) was demonstrated by metabolism analysis of (3)H-steroids. All the enzymes required for corticosteroid synthesis including P450(c21), P450(2D4), P450(11β1) and 3β-hydroxysteroid dehydrogenase (3β-HSD) were localized in the hippocampal principal neurons as shown via in situ hybridization and immunoelectron microscopic analysis. Accurate corticosteroid concentrations in rat hippocampus were determined by liquid chromatography-tandem mass spectrometry. In adrenalectomized rats, net hippocampus-synthesized corticosterone (CORT) and DOC were determined to 6.9 and 5.8 nM, respectively. Enhanced spinogenesis was observed in the hippocampus following application of low nanomolar (10 nM) doses of CORT for 1 h. CONCLUSIONS/SIGNIFICANCE These results imply the complete pathway of corticosteroid synthesis of 'pregnenolone →PROG→DOC→CORT' in the hippocampal neurons. Both P450(c21) and P450(2D4) can catalyze conversion of PROG to DOC. The low nanomolar level of CORT synthesized in hippocampal neurons may play a role in modulation of synaptic plasticity, in contrast to the stress effects by micromolar CORT from adrenal glands.
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Affiliation(s)
- Shimpei Higo
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo, Japan
| | - Yasushi Hojo
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo, Japan
- Core Research for Evolutional Science and Technology Project of Japan Science and Technology Agency, The University of Tokyo, Meguro, Tokyo, Japan
- Bioinformatics Project of Japan Science and Technology Agency, The University of Tokyo, Meguro, Tokyo, Japan
| | - Hirotaka Ishii
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo, Japan
| | - Yoshimasa Komatsuzaki
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo, Japan
- Department of Physics, College of Science and Technology, Nihon University, Chiyoda, Tokyo, Japan
| | - Yuuki Ooishi
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo, Japan
| | - Gen Murakami
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo, Japan
- Bioinformatics Project of Japan Science and Technology Agency, The University of Tokyo, Meguro, Tokyo, Japan
| | - Hideo Mukai
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo, Japan
- Core Research for Evolutional Science and Technology Project of Japan Science and Technology Agency, The University of Tokyo, Meguro, Tokyo, Japan
- Bioinformatics Project of Japan Science and Technology Agency, The University of Tokyo, Meguro, Tokyo, Japan
| | - Takeshi Yamazaki
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, Japan
| | - Daiichiro Nakahara
- Department of Psychology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Anna Barron
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo, Japan
| | - Tetsuya Kimoto
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo, Japan
| | - Suguru Kawato
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo, Japan
- Core Research for Evolutional Science and Technology Project of Japan Science and Technology Agency, The University of Tokyo, Meguro, Tokyo, Japan
- Bioinformatics Project of Japan Science and Technology Agency, The University of Tokyo, Meguro, Tokyo, Japan
- * E-mail:
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29
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Taves MD, Gomez-Sanchez CE, Soma KK. Extra-adrenal glucocorticoids and mineralocorticoids: evidence for local synthesis, regulation, and function. Am J Physiol Endocrinol Metab 2011; 301:E11-24. [PMID: 21540450 PMCID: PMC3275156 DOI: 10.1152/ajpendo.00100.2011] [Citation(s) in RCA: 189] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Glucocorticoids and mineralocorticoids are steroid hormones classically thought to be secreted exclusively by the adrenal glands. However, recent evidence has shown that corticosteroids can also be locally synthesized in various other tissues, including primary lymphoid organs, intestine, skin, brain, and possibly heart. Evidence for local synthesis includes detection of steroidogenic enzymes and high local corticosteroid levels, even after adrenalectomy. Local synthesis creates high corticosteroid concentrations in extra-adrenal organs, sometimes much higher than circulating concentrations. Interestingly, local corticosteroid synthesis can be regulated via locally expressed mediators of the hypothalamic-pituitary-adrenal (HPA) axis or renin-angiotensin system (RAS). In some tissues (e.g., skin), these local control pathways might form miniature analogs of the pathways that regulate adrenal corticosteroid production. Locally synthesized glucocorticoids regulate activation of immune cells, while locally synthesized mineralocorticoids regulate blood volume and pressure. The physiological importance of extra-adrenal glucocorticoids and mineralocorticoids has been shown, because inhibition of local synthesis has major effects even in adrenal-intact subjects. In sum, while adrenal secretion of glucocorticoids and mineralocorticoids into the blood coordinates multiple organ systems, local synthesis of corticosteroids results in high spatial specificity of steroid action. Taken together, studies of these five major organ systems challenge the conventional understanding of corticosteroid biosynthesis and function.
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Affiliation(s)
- Matthew D Taves
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada.
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30
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Gomez-Sanchez EP. Mineralocorticoid receptors in the brain and cardiovascular regulation: minority rule? Trends Endocrinol Metab 2011; 22:179-87. [PMID: 21429762 PMCID: PMC3140534 DOI: 10.1016/j.tem.2011.02.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 01/28/2011] [Accepted: 02/02/2011] [Indexed: 01/05/2023]
Abstract
A small proportion of brain mineralocorticoid receptors (MR) mediate control of blood pressure, water and electrolyte balance, sodium appetite, and sympathetic drive to the periphery. Circulating inflammatory cytokines modulate MR-mediated changes in sympathoexcitation. Aldosterone binding to MR in the brain occurs, despite concentrations that are 2-3 orders of magnitude less than those of cortisol and corticosterone, which have similar affinity for the MR. The possible mechanisms for selective MR activation by aldosterone, the cellular mechanisms of MR action and the effects of brain MR on hemodynamic homeostasis are considered in this review. MR antagonists are valuable adjuncts to the treatment of chronic cardiovascular and renal disease; the crucial need to discover targets for development of selective therapy for specific MR functions is also discussed.
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Affiliation(s)
- Elise P Gomez-Sanchez
- Research Service, G.V. (Sonny) Montgomery VA Medical Center and Department of Medicine, Division of Endocrinology, The University of Mississippi Medical Center, Jackson, MO, USA.
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31
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Munetsuna E, Hattori M, Sakimoto Y, Ishida A, Sakata S, Hojo Y, Kawato S, Yamazaki T. Environmental enrichment alters gene expression of steroidogenic enzymes in the rat hippocampus. Gen Comp Endocrinol 2011; 171:28-32. [PMID: 21172348 DOI: 10.1016/j.ygcen.2010.12.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 11/06/2010] [Accepted: 12/12/2010] [Indexed: 11/27/2022]
Abstract
Neuroactive steroids are synthesized in the central and peripheral nervous systems. The purpose of this study was to analyze the effects of environmental enrichment on neuroactive steroidogenesis in the rat hippocampus. Environmental enrichment rats were housed in a group of nine in a large cage and three groups of pair-housed rats were housed in a standard cage for 8 weeks. The levels of mRNAs for steroidogenic enzymes and proteins in hippocampus were quantified by real-time RT-PCR. Environmental enrichment increased the mRNA expression levels of 5α-reductase-1 and 3α-hydroxysteroid dehydrogenase, which catalyze synthesis of allopregnanolone from progesterone. Hence, environmental enrichment appears to affect allopregnanolone synthesis.
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Affiliation(s)
- Eiji Munetsuna
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima 739-8521, Japan
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32
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Huang BS, Leenen FHH. Mineralocorticoid Actions in the Brain and Hypertension. Curr Hypertens Rep 2011; 13:214-20. [DOI: 10.1007/s11906-011-0192-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Riedemann T, Patchev AV, Cho K, Almeida OFX. Corticosteroids: way upstream. Mol Brain 2010; 3:2. [PMID: 20180948 PMCID: PMC2841592 DOI: 10.1186/1756-6606-3-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 01/11/2010] [Indexed: 01/20/2023] Open
Abstract
Studies into the mechanisms of corticosteroid action continue to be a rich bed of research, spanning the fields of neuroscience and endocrinology through to immunology and metabolism. However, the vast literature generated, in particular with respect to corticosteroid actions in the brain, tends to be contentious, with some aspects suffering from loose definitions, poorly-defined models, and appropriate dissection kits. Here, rather than presenting a comprehensive review of the subject, we aim to present a critique of key concepts that have emerged over the years so as to stimulate new thoughts in the field by identifying apparent shortcomings. This article will draw on experience and knowledge derived from studies of the neural actions of other steroid hormones, in particular estrogens, not only because there are many parallels but also because 'learning from differences' can be a fruitful approach. The core purpose of this review is to consider the mechanisms through which corticosteroids might act rapidly to alter neural signaling.
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Affiliation(s)
- Therese Riedemann
- Max-Planck-Institute of Psychiatry, Kraepelin Str. 2-10, 80804 Munich, Germany
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Faculty of Medicine and Dentistry, University of Bristol, Bristol, UK
| | - Alexandre V Patchev
- Max-Planck-Institute of Psychiatry, Kraepelin Str. 2-10, 80804 Munich, Germany
| | - Kwangwook Cho
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Faculty of Medicine and Dentistry, University of Bristol, Bristol, UK
| | - Osborne FX Almeida
- Max-Planck-Institute of Psychiatry, Kraepelin Str. 2-10, 80804 Munich, Germany
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Westcott KV, Huang BS, Leenen FH. Brain renin–angiotensin–aldosterone system and ventricular remodeling after myocardial infarct: a reviewThis article is one of a selection of papers published in a special issue on Advances in Cardiovascular Research. Can J Physiol Pharmacol 2009; 87:979-88. [DOI: 10.1139/y09-067] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
After a myocardial infarct (MI), a variety of mechanisms contribute to progressive cardiac remodeling and dysfunction. Progressive activation of central sympathoexcitatory pathways appears to depend on a neuromodulatory pathway, involving local production of aldosterone and release of endogenous ouabain-like compounds (‘ouabain’) possibly from magnocellular neurons in the supraoptic and paraventricular nuclei. ‘Ouabain’ may lower the membrane potential of neurons and thereby enhance activity of angiotensinergic pathways. These central pathways appear to coordinate progressive activation of several peripheral mechanisms such as sympathetic tone and circulating and cardiac renin–angiotensin–aldosterone system (RAAS). Central blockade of aldosterone production, mineralocorticoid receptors, ‘ouabain’ activity, or AT1 receptors similarly prevents activation of these peripheral mechanisms. Cardiac remodeling after MI involves progressive left ventricular dilation, fibrosis, and decrease in contractile performance. Central blockade of this neuromodulatory pathway causes a marked attenuation of the remodeling and dysfunction, presumably by inhibiting increases in (cardiac) sympathetic activity and RAAS. At the cellular level, these systems may contribute to the cardiac remodeling by activating proinflammatory cytokines and cardiac myocyte apoptosis. New therapeutic approaches, specifically preventing activation of this brain neuromodulatory pathway, may lead to more optimal and specific approaches to the prevention of heart failure after MI.
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Affiliation(s)
- Katherine V. Westcott
- Hypertension Unit, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, ON K1Y 4W7, Canada
| | - Bing S. Huang
- Hypertension Unit, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, ON K1Y 4W7, Canada
| | - Frans H.H. Leenen
- Hypertension Unit, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, ON K1Y 4W7, Canada
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35
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Schmidt KL, Chin EH, Shah AH, Soma KK. Cortisol and corticosterone in immune organs and brain of European starlings: developmental changes, effects of restraint stress, comparison with zebra finches. Am J Physiol Regul Integr Comp Physiol 2009; 297:R42-51. [DOI: 10.1152/ajpregu.90964.2008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Glucocorticoids (GCs) are produced in the adrenal glands and also in extra-adrenal sites, including immune organs and brain. Here, we examined regulation of systemic GC levels in plasma and local GC levels in immune organs and brain during development. We conducted two studies and examined a total of 462 samples from 70 subjects. In study 1, we determined corticosterone and cortisol levels in the plasma, immune organs, and brain of wild European starlings on posthatch day 0 (P0) and P10 (at baseline and after 45 min of restraint). Baseline corticosterone and cortisol levels were low in the immune organs and brain at P0 and P10, providing little evidence for local GC synthesis in starlings. At P0, restraint had no significant effects on corticosterone or cortisol levels in the plasma or tissues; however, there was a trend for restraint to increase both corticosterone and cortisol in the immune organs. At P10, restraint increased corticosterone levels in the plasma and all tissues, but restraint increased cortisol levels in the plasma, thymus, and diencephalon only. In study 2, we directly compared GC levels in European starlings and zebra finches at P4. In zebra finches but not starlings, cortisol levels were higher in the immune organs than in plasma. This difference in immune GC levels might be due to evolutionary lineage, life history strategy, or experiential factors, such as parasite exposure. This is the first study to measure immune GC levels in wild animals and one of the first studies to measure local GC levels after restraint stress.
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36
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Bielohuby M, Roemmler J, Manolopoulou J, Johnsen I, Sawitzky M, Schopohl J, Reincke M, Wolf E, Hoeflich A, Bidlingmaier M. Chronic growth hormone excess is associated with increased aldosterone: a study in patients with acromegaly and in growth hormone transgenic mice. Exp Biol Med (Maywood) 2009; 234:1002-9. [PMID: 19491373 DOI: 10.3181/0901-rm-34] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Acromegaly is a disease characterized by chronic growth hormone (GH) excess. Since hypertension is a common finding in patients with acromegaly, interactions between GH and the renin-angiotensin-aldosterone system (RAAS) are under controversial debate. We examined GH, IGF-I, aldosterone, and renin in a well-defined group of acromegalic patients before and after cure by surgery. In addition, we analyzed the impact of chronic GH excess on the RAAS in mouse models over-expressing GH alone (G) or in combination with insulin-like growth factor-binding protein-2 (IGFBP-2; GB). Normalization of GH secretion after cure by surgery was accompanied by significant decreases of serum aldosterone in acromegalic patients (pre-op: 96.5 +/- 37.1 pg/mL, post-op: 41.3 +/- 28.2 pg/ mL; P < 0.001; n = 13), but renin concentrations were unaffected. In addition, aldosterone concentrations were positively correlated to GH levels (Spearman r = 0.39; P = 0.025; n = 26). To further study this association, we analysed two transgenic mouse models and found a similar relationship between GH and aldosterone in G mice, which showed about 3-fold elevated serum aldosterone levels in comparison to non-transgenic controls (males: 442 +/- 331 pg/mL vs. 151 +/- 84 pg/mL; P = 0.002; n > or = 12; females: 488 +/- 161 pg/mL vs. 108 +/- 125 pg/mL; P = 0.05; n > or = 4). Expression of aldosterone synthase was similar in adrenal glands of C and G mice. Aldosterone levels in G and GB mice of both genders were not different, indicating that the elevated aldosterone was due to GH excess and not caused by elevated IGF-I, which is known to be blocked by IGFBP-2 overexpression. Also in the mouse models, changes in aldosterone were independent from renin. In summary, we show that chronic GH excess is associated with increased aldosterone in humans and mice. GH-induced increases of aldosterone potentially contribute to the increased cardiovascular risk in acromegalic patients. The underlying mechanism is likely to be independent of renin, excess IGF-I, or adrenal aldosterone synthase expression.
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Affiliation(s)
- Maximilian Bielohuby
- Medizinische Klinik - Innenstadt Klinikum der Universität, Ziemssenstr. 1, 80336 Munich, Germany
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37
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Current world literature. Curr Opin Endocrinol Diabetes Obes 2009; 16:260-77. [PMID: 19390324 DOI: 10.1097/med.0b013e32832c937e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Huang BS, Leenen FHH. The brain renin-angiotensin-aldosterone system: A major mechanism for sympathetic hyperactivity and left ventricular remodeling and dysfunction after myocardial infarction. Curr Heart Fail Rep 2009; 6:81-8. [DOI: 10.1007/s11897-009-0013-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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39
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McManus F, MacKenzie SM, Freel EM. Central mineralocorticoid receptors, sympathetic activity, and hypertension. Curr Hypertens Rep 2009; 11:224-30. [DOI: 10.1007/s11906-009-0039-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Newman AEM, Soma KK. Corticosterone and dehydroepiandrosterone in songbird plasma and brain: effects of season and acute stress. Eur J Neurosci 2009; 29:1905-14. [PMID: 19473242 DOI: 10.1111/j.1460-9568.2009.06748.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Prolonged increases in plasma glucocorticoids can exacerbate neurodegeneration. In rats, these neurodegenerative effects can be reduced by dehydroepiandrosterone (DHEA), an androgen precursor with anti-glucocorticoid actions. In song sparrows, season and acute restraint stress affect circulating levels of corticosterone and DHEA, and the effects of stress differ in plasma collected from the brachial and jugular veins. Jugular plasma is an indirect index of the neural steroidal milieu. Here, we directly measured corticosterone and DHEA in several brain regions and jugular plasma, and examined the effects of season and acute restraint stress (30 min) (n = 571 samples). Corticosterone levels were up to 10x lower in brain than in jugular plasma. In contrast, DHEA levels were up to 5x higher in brain than in jugular plasma and were highest in the hippocampus. Corticosterone and DHEA concentrations were strongly seasonally regulated in plasma but, surprisingly, not seasonally regulated in brain. Acute stress increased corticosterone levels in plasma and brain, except during the molt, when stress unexpectedly decreased corticosterone levels in the hippocampus. Acute stress increased DHEA levels in plasma during the molt but had no effects on DHEA levels in brain. This is the first study to measure (i) corticosterone or DHEA levels in the brain of adult songbirds and (ii) seasonal changes in corticosterone or DHEA levels in the brain of any species. These results highlight several critical differences between systemic and local steroid concentrations and the difficulty of using circulating steroid levels to infer local steroid levels within the brain.
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Affiliation(s)
- Amy E M Newman
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada.
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Huang BS, White RA, Jeng AY, Leenen FHH. Role of central nervous system aldosterone synthase and mineralocorticoid receptors in salt-induced hypertension in Dahl salt-sensitive rats. Am J Physiol Regul Integr Comp Physiol 2009; 296:R994-R1000. [DOI: 10.1152/ajpregu.90903.2008] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In Dahl salt-sensitive (S) rats, high salt intake increases cerebrospinal fluid (CSF) Na+ concentration ([Na+]) and blood pressure (BP). Intracerebroventricular (ICV) infusion of a mineralocorticoid receptor (MR) blocker prevents the hypertension. To assess the role of aldosterone locally produced in the brain, we evaluated the effects of chronic central blockade with the aldosterone synthase inhibitor FAD286 and the MR blocker spironolactone on changes in aldosterone and corticosterone content in the hypothalamus and the increase in CSF [Na+] and hypertension induced by high salt intake in Dahl S rats. After 4 wk of high salt intake, plasma aldosterone and corticosterone were not changed, but hypothalamic aldosterone increased by ∼35% and corticosterone tended to increase in Dahl S rats, whereas both steroids decreased by ∼65% in Dahl salt-resistant rats. In Dahl S rats fed the high-salt diet, ICV infusion of FAD286 or spironolactone did not affect the increase in CSF [Na+]. ICV infusion of FAD286 prevented the increase in hypothalamic aldosterone and 30 mmHg of the 50-mmHg BP increase induced by high salt intake. ICV infusion of spironolactone fully prevented the salt-induced hypertension. These results suggest that, in Dahl S rats, high salt intake increases aldosterone synthesis in the hypothalamus and aldosterone acts as the main MR agonist activating central pathways contributing to salt-induced hypertension.
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Abstract
Pharmacological and physiological phenomena suggest that cells somewhere inside the central nervous system are responsive to aldosterone. Here, we present the fundamental physiological limitations for aldosterone action in the brain, including its limited blood-brain barrier penetration and its substantial competition from glucocorticoids. Recently, a small group of neurons with unusual sensitivity to circulating aldosterone were identified in the nucleus of the solitary tract. We review the discovery and characterization of these neurons, which express the enzyme 11beta-hydroxysteroid dehydrogenase type 2, and consider alternative proposals regarding sites and mechanisms for mineralocorticoid action within the brain.
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Affiliation(s)
- Joel C Geerling
- Dept. of Anatomy and Neurobiology-Box 8108, Washington Univ. School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA.
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