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Araujo JEDS, Miguel-dos-Santos R, Macedo FN, Cunha PS, Fontes MT, Murata GM, Lauton-Santos S, Santana-Filho VJ, Silva AMDO, Antoniolli AR, Curi R, Quintans JDSS, Barreto RDSS, Santos MRV, Quintans-Junior LJ, Barreto AS. Effects of high doses of glucocorticoids on insulin-mediated vasodilation in the mesenteric artery of rats. PLoS One 2020; 15:e0230514. [PMID: 32187237 PMCID: PMC7080254 DOI: 10.1371/journal.pone.0230514] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 03/02/2020] [Indexed: 01/11/2023] Open
Abstract
Several pathological conditions predict the use of glucocorticoids for the management of the inflammatory response; however, chronic or high dose glucocorticoid treatment is associated with hyperglycemia, hyperlipidemia, and insulin resistance and can be considered a risk factor for cardiovascular disease. Therefore, we investigated the mechanisms involved in the vascular responsiveness and inflammatory profile of mesenteric arteries of rats treated with high doses of glucocorticoids. Wistar rats were divided into a control (CO) group and a dexamethasone (DEX) group, that received dexamethasone for 7 days (2mg/kg/day, i.p.). Blood samples were used to assess the lipid profile and insulin tolerance. Vascular reactivity to Phenylephrine (Phe) and insulin, and O2•-production were evaluated. The intracellular insulin signaling pathway PI3K/AKT/eNOS and MAPK/ET-1 were investigated. Regarding the vascular inflammatory profile, TNF-α, IL-6, IL-1β and IL-18 were assessed. Dexamethasone-treated rats had decreased insulin tolerance test and endothelium-dependent vasodilation induced by insulin. eNOS inhibition caused vasoconstriction in the DEX group, which was abolished by the ET-A antagonist. Insulin-mediated relaxation in the DEX group was restored in the presence of the O2.- scavenger TIRON. Nevertheless, in the DEX group there was an increase in Phe-induced vasoconstriction. In addition, the intracellular insulin signaling pathway PI3K/AKT/eNOS was impaired, decreasing NO bioavailability. Regarding superoxide anion generation, there was an increase in the DEX group, and all measured proinflammatory cytokines were also augmented in the DEX group. In addition, the DEX-group presented an increase in low-density lipoprotein cholesterol (LDL-c) and total cholesterol (TC) and reduced high-density lipoprotein cholesterol (HDL-c) levels. In summary, treatment with high doses of dexamethasone promoted changes in insulin-induced vasodilation, through the reduction of NO bioavailability and an increase in vasoconstriction via ET-1 associated with generation of O2•- and proinflammatory cytokines.
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Affiliation(s)
- João Eliakim dos S. Araujo
- Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe, Sao Cristovao, Sergipe, Brazil
| | - Rodrigo Miguel-dos-Santos
- Laboratory of Cardiovascular Biology and Oxidative Stress, Department of Physiology, Federal University of Sergipe, Sao Cristovao, Sergipe, Brazil
| | | | - Patrícia S. Cunha
- Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe, Sao Cristovao, Sergipe, Brazil
| | - Milene Tavares Fontes
- Vascular Physiology Laboratory, Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Gilson Masahiro Murata
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Sandra Lauton-Santos
- Laboratory of Cardiovascular Biology and Oxidative Stress, Department of Physiology, Federal University of Sergipe, Sao Cristovao, Sergipe, Brazil
| | - Valter J. Santana-Filho
- Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe, Sao Cristovao, Sergipe, Brazil
| | - Ana Mara de O. Silva
- Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe, Sao Cristovao, Sergipe, Brazil
| | - Angelo Roberto Antoniolli
- Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe, Sao Cristovao, Sergipe, Brazil
| | - Rui Curi
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Jullyana de S. S. Quintans
- Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe, Sao Cristovao, Sergipe, Brazil
| | - Rosana de S. S. Barreto
- Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe, Sao Cristovao, Sergipe, Brazil
| | - Marcio R. V. Santos
- Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe, Sao Cristovao, Sergipe, Brazil
| | - Lucindo J. Quintans-Junior
- Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe, Sao Cristovao, Sergipe, Brazil
| | - André S. Barreto
- Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe, Sao Cristovao, Sergipe, Brazil
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ARAUJO JOÃOE, MACEDO FABRÍCION, OLIVEIRA DAVIP, BRITTO RAQUELM, QUINTANS JULLYANAS, BARRETO ROSANAS, SANTOS MARCIOR, QUINTANS-JUNIOR LUCINDOJ, BARRETO ANDRÉS. Resistance training prevents the reduction of insulin-mediated vasodilation in the mesenteric artery of dexamethasone-treated rats. AN ACAD BRAS CIENC 2020; 92:e20200316. [DOI: 10.1590/0001-3765202020200316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 07/22/2020] [Indexed: 12/30/2022] Open
Affiliation(s)
- JOÃO E.S. ARAUJO
- Universidade Federal de Sergipe, Brazil; Programa de Pós-Graduação em Ciências da Saúde, Brazil; Universidade Tiradentes, Brazil
| | | | | | | | - JULLYANA S.S. QUINTANS
- Universidade Federal de Sergipe, Brazil; Programa de Pós-Graduação em Ciências da Saúde, Brazil
| | - ROSANA S.S. BARRETO
- Universidade Federal de Sergipe, Brazil; Programa de Pós-Graduação em Ciências da Saúde, Brazil
| | - MARCIO R.V. SANTOS
- Universidade Federal de Sergipe, Brazil; Programa de Pós-Graduação em Ciências da Saúde, Brazil
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El-Sonbaty YA, Suddek GM, Megahed N, Gameil NM. Protocatechuic acid exhibits hepatoprotective, vasculoprotective, antioxidant and insulin-like effects in dexamethasone-induced insulin-resistant rats. Biochimie 2019; 167:119-134. [PMID: 31557503 DOI: 10.1016/j.biochi.2019.09.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 09/16/2019] [Indexed: 12/28/2022]
Abstract
Protocatechuic acid (PCA), the natural phenolic antioxidant, reportedly exhibited hypoglycemic and insulin-like effects. Recent studies have reported its cardioprotective effect in glucocorticoid (GC)-induced hypertensive rats. Nevertheless, its beneficial role has not been investigated in the setting of GCs excess-induced insulin resistance. This study aimed to investigate the possible protective potential and the plausible mechanisms of pretreatment with PCA against GCs-induced insulin resistance, liver steatosis and vascular dysfunction. Insulin resistance was induced in male Wistar rats by a 7-day treatment with dexamethasone (DEX) (1 mg/kg/day, i.p.). PCA (50, 100 mg/kg/day, orally) was started 7 days before DEX administration and continued during the test period. PCA significantly and dose-dependently attenuated DEX-induced a) glucose intolerance (↓ AUCOGTT), b) hyperglycemia (↓ fasting blood glucose), c) impaired insulin sensitivity [↓fasting plasma insulin and homeostasis model assessment of insulin resistance (HOMA-IR) index)] and d) dyslipidemia (↓total cholesterol, triglycerides, low-density lipoprotein-cholesterol and very low-density lipoprotein-cholesterol). PCA mitigated DEX-induced liver steatosis with associated reduction in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity. Moreover, PCA ameliorated DEX-induced vascular dysfunction and enhanced ACh-induced relaxation in aortic rings. The metabolic ameliorating effects of PCA might be attributed to the enhanced insulin signaling in soleus muscles (↑AKT phosphorylation) and mitigating gluconeogenesis (↓ hepatic mRNA expression of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase). The vasculoprotective effect of PCA might be related to its ability to restore normal mRNA expression of [endothelial nitric oxide synthase (eNOS) and NADPH Oxidase 4 (NOX4)]. PCA restored normal oxidative balance [↓ oxidant species, malondialdehyde (MDA) and (↑ antioxidant superoxide dismutase (SOD)]. The findings herein reveal for the first time that PCA may be taken as a supplement with GCs to limit their metabolic and vascular side effects through its hypoglycemic, insulin-sensitizing, hypolipidemic and antioxidant effects.
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Affiliation(s)
- Yomna A El-Sonbaty
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt.
| | - Ghada M Suddek
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
| | - Nirmeen Megahed
- Department of Pathology, Faculty of Medicine, Mansoura University, Egypt
| | - Nariman M Gameil
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
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Dunford EC, Riddell MC. The Metabolic Implications of Glucocorticoids in a High-Fat Diet Setting and the Counter-Effects of Exercise. Metabolites 2016; 6:metabo6040044. [PMID: 27929385 PMCID: PMC5192450 DOI: 10.3390/metabo6040044] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 11/25/2016] [Accepted: 11/30/2016] [Indexed: 02/06/2023] Open
Abstract
Glucocorticoids (GCs) are steroid hormones, naturally produced by activation of the hypothalamic-pituitary-adrenal (HPA) axis, that mediate the immune and metabolic systems. Synthetic GCs are used to treat a number of inflammatory conditions and diseases including lupus and rheumatoid arthritis. Generally, chronic or high dose GC administration is associated with side effects such as steroid-induced skeletal muscle loss, visceral adiposity, and diabetes development. Patients who are taking exogenous GCs could also be more susceptible to poor food choices, but the effect that increasing fat consumption in combination with elevated exogenous GCs has only recently been investigated. Overall, these studies show that the damaging metabolic effects initiated through exogenous GC treatment are significantly amplified when combined with a high fat diet (HFD). Rodent studies of a HFD and elevated GCs demonstrate more glucose intolerance, hyperinsulinemia, visceral adiposity, and skeletal muscle lipid deposition when compared to rodents subjected to either treatment on its own. Exercise has recently been shown to be a viable therapeutic option for GC-treated, high-fat fed rodents, with the potential mechanisms still being examined. Clinically, these mechanistic studies underscore the importance of a low fat diet and increased physical activity levels when individuals are given a course of GC treatment.
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Affiliation(s)
- Emily C Dunford
- School of Kinesiology and Health Science, Faculty of Health, Muscle Health Research Center and Physical Activity and Chronic Disease Unit, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada.
| | - Michael C Riddell
- School of Kinesiology and Health Science, Faculty of Health, Muscle Health Research Center and Physical Activity and Chronic Disease Unit, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada.
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Brennan KM, Urschel KL. Recovery of insulin sensitivity in mature horses after a 3 week course of dexamethasone therapy. Equine Vet J 2014; 46:718-21. [PMID: 24533602 DOI: 10.1111/evj.12242] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 02/11/2014] [Indexed: 12/23/2022]
Abstract
REASONS FOR PERFORMING THE STUDY Dexamethasone is an anti-inflammatory drug commonly used in equine medicine. Insulin sensitivity decreases with prolonged dexamethasone administration, but little information is available about the duration of this side effect after long-term treatment ends. OBJECTIVES To determine how long it takes for blood glucose, insulin and markers of insulin sensitivity to return to normal ranges after extended dexamethasone treatment has ceased. STUDY DESIGN Experimental study. METHODS Eight healthy, mature, mixed-breed horses received 0.04 mg/kg bwt/day oral dexamethasone for 21 days. Blood samples were taken weekly during dexamethasone treatment (Days -21, -14 and -7). Following the final dose of dexamethasone on Day 0, blood samples were taken on Days 1-6, 8, 10, 12, 15 and 22. Day -21 represents baseline or normal blood predexamethasone. RESULTS On Day 1, plasma glucose and insulin concentrations and the modified insulin-to-glucose ratio (a proxy for pancreatic β cell responsiveness) were higher and the reciprocal of the square root of insulin (a proxy for the estimate of insulin sensitivity) was lower, in comparison with Day -21 values. Blood glucose concentrations dropped and returned to Day -21 values by Day 2. Insulin concentrations remained elevated until Day 3. Values for the modified insulin-to-glucose ratio decreased and returned to Day -21 concentrations by Day 4. Values for the reciprocal of the square root of insulin did not return to Day -21 values until Day 15. CONCLUSIONS These results indicate that, in contrast to blood glucose concentrations, which return to normal quickly (within 2 days after treatment ends), the pancreatic insulin-secreting response has a delayed recovery.
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Affiliation(s)
- K M Brennan
- Center for Animal Nutrigenomics and Applied Animal Nutrition, Alltech Inc, Nicholasville, Kentucky, USA
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Boscaro M, Giacchetti G, Ronconi V. Visceral adipose tissue: emerging role of gluco- and mineralocorticoid hormones in the setting of cardiometabolic alterations. Ann N Y Acad Sci 2012; 1264:87-102. [PMID: 22804097 PMCID: PMC3464353 DOI: 10.1111/j.1749-6632.2012.06597.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Several clinical and experimental lines of evidence have highlighted the detrimental effects of visceral adipose tissue excess on cardiometabolic parameters. Besides, recent findings have shown the effects of gluco-and mineralocorticoid hormones on adipose tissue and have also underscored the interplay existing between such adrenal steroids and their respective receptors in the modulation of adipose tissue biology. While the fundamental role played by glucocorticoids on adipocyte differentiation and storage was already well known, the relevance of the mineralocorticoids in the physiology of the adipose organ is of recent acquisition. The local and systemic renin–angiotensin–aldosterone system (RAAS) acting on adipose tissue seems to contribute to the development of the cardiometabolic phenotype so that its modulation can have deep impact on human health. A better understanding of the pathophysiology of the adipose organ is of crucial importance in order to identify possible therapeutic approaches that can avoid the development of such cardiovascular and metabolic sequelae.
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Affiliation(s)
- Marco Boscaro
- Division of Endocrinology, Ospedali Riuniti "Umberto I-G.M. Lancisi-G. Salesi," Università Politecnica delle Marche, Ancona, Italy
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FUKUTA H, MORI A, URUMUHAN N, LEE P, ODA H, SAEKI K, KURISHIMA M, NOZAWA S, MIZUTANI H, MISHINA S, ARAI T, SAKO T. Characterization and Comparison of Insulin Resistance Induced by Cushing Syndrome or Diestrus against Healthy Control Dogs as Determined by Euglycemic- Hyperinsulinemic Glucose Clamp Profile Glucose Infusion Rate Using an Artificial Pancreas Apparatus. J Vet Med Sci 2012; 74:1527-30. [DOI: 10.1292/jvms.12-0041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Hiroko FUKUTA
- Department of Veterinary Nursing and Technology, School of Veterinary Science, Nippon Veterinary and Life Science University, 1–7–1 Kyonancho, Musashino, Tokyo 180–8602, Japan
| | - Akihiro MORI
- Department of Veterinary Nursing and Technology, School of Veterinary Science, Nippon Veterinary and Life Science University, 1–7–1 Kyonancho, Musashino, Tokyo 180–8602, Japan
| | - Nazarbek URUMUHAN
- Department of Veterinary Nursing and Technology, School of Veterinary Science, Nippon Veterinary and Life Science University, 1–7–1 Kyonancho, Musashino, Tokyo 180–8602, Japan
| | - Peter LEE
- Department of Veterinary Medicine, School of Veterinary Science, Nippon Veterinary and Life Science University, 1–7–1 Kyonancho, Musashino, Tokyo 180–8602, Japan
| | - Hitomi ODA
- Department of Veterinary Nursing and Technology, School of Veterinary Science, Nippon Veterinary and Life Science University, 1–7–1 Kyonancho, Musashino, Tokyo 180–8602, Japan
| | - Kaori SAEKI
- Department of Veterinary Nursing and Technology, School of Veterinary Science, Nippon Veterinary and Life Science University, 1–7–1 Kyonancho, Musashino, Tokyo 180–8602, Japan
| | - Miyuki KURISHIMA
- Department of Veterinary Nursing and Technology, School of Veterinary Science, Nippon Veterinary and Life Science University, 1–7–1 Kyonancho, Musashino, Tokyo 180–8602, Japan
| | - Satoshi NOZAWA
- Department of Veterinary Nursing and Technology, School of Veterinary Science, Nippon Veterinary and Life Science University, 1–7–1 Kyonancho, Musashino, Tokyo 180–8602, Japan
| | - Hisashi MIZUTANI
- Department of Veterinary Medicine, School of Veterinary Science, Nippon Veterinary and Life Science University, 1–7–1 Kyonancho, Musashino, Tokyo 180–8602, Japan
| | - Suguru MISHINA
- Nikkiso Co., Ltd., 4–20–3 Ebisu, Shibuya-ku, Tokyo 150–6022, Japan
| | - Toshiro ARAI
- Department of Veterinary Medicine, School of Veterinary Science, Nippon Veterinary and Life Science University, 1–7–1 Kyonancho, Musashino, Tokyo 180–8602, Japan
| | - Toshinori SAKO
- Department of Veterinary Nursing and Technology, School of Veterinary Science, Nippon Veterinary and Life Science University, 1–7–1 Kyonancho, Musashino, Tokyo 180–8602, Japan
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Castañeda TR, Nogueiras R, Müller TD, Krishna R, Grant E, Jones A, Ottaway N, Ananthakrishnan G, Pfluger PT, Chaudhary N, Solomon MB, Woods SC, Herman JP, Tschöp MH. Decreased glucose tolerance and plasma adiponectin:resistin ratio in a mouse model of post-traumatic stress disorder. Diabetologia 2011; 54:900-9. [PMID: 21181395 DOI: 10.1007/s00125-010-2019-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 11/25/2010] [Indexed: 10/18/2022]
Abstract
AIMS/HYPOTHESIS Obesity and type 2 diabetes are among the most serious health pathologies worldwide. Stress has been proposed as a factor contributing to the development of these health risk factors; however, the underlying mechanisms that link stress to obesity and diabetes need to be further clarified. Here, we study in mice how chronic stress affects dietary consumption and how that relationship contributes to obesity and diabetes. METHODS C57BL/6J mice were subjected to chronic variable stress (CVS) for 15 days and subsequently fed with a standard chow or high-fat diet. Food intake, body weight, respiratory quotient, energy expenditure and spontaneous physical activity were measured with a customised calorimetric system and body composition was measured with nuclear magnetic resonance. A glucose tolerance test was also applied and blood glucose levels were measured with a glucometer. Plasma levels of adiponectin and resistin were measured using Lincoplex kits. RESULTS Mice under CVS and fed with a high-fat diet showed impaired glucose tolerance associated with low plasma adiponectin:resistin ratios. CONCLUSIONS/INTERPRETATION This study demonstrates, in a novel mouse model, how post-traumatic stress disorder enhances vulnerability for impaired glucose metabolism in an energy-rich environment and proposes a potential adipokine-based mechanism.
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Affiliation(s)
- T R Castañeda
- Department of Medicinal and Biological Chemistry, College of Pharmacy and Center for Diabetes and Endocrine Research, College of Medicine, University of Toledo, Toledo, OH, USA
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Barel M, Perez OAB, Giozzet VA, Rafacho A, Bosqueiro JR, do Amaral SL. Exercise training prevents hyperinsulinemia, muscular glycogen loss and muscle atrophy induced by dexamethasone treatment. Eur J Appl Physiol 2009; 108:999-1007. [DOI: 10.1007/s00421-009-1272-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/22/2009] [Indexed: 01/08/2023]
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Nieuwenhuizen AG, Rutters F. The hypothalamic-pituitary-adrenal-axis in the regulation of energy balance. Physiol Behav 2008; 94:169-77. [DOI: 10.1016/j.physbeh.2007.12.011] [Citation(s) in RCA: 165] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 12/13/2007] [Accepted: 12/17/2007] [Indexed: 10/22/2022]
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Christ-Crain M, Kola B, Lolli F, Fekete C, Seboek D, Wittmann G, Feltrin D, Igreja SC, Ajodha S, Harvey-White J, Kunos G, Müller B, Pralong F, Aubert G, Arnaldi G, Giacchetti G, Boscaro M, Grossman AB, Korbonits M. AMP-activated protein kinase mediates glucocorticoid-induced metabolic changes: a novel mechanism in Cushing's syndrome. FASEB J 2008; 22:1672-83. [PMID: 18198220 DOI: 10.1096/fj.07-094144] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chronic exposure to glucocorticoid hormones, resulting from either drug treatment or Cushing's syndrome, results in insulin resistance, central obesity, and symptoms similar to the metabolic syndrome. We hypothesized that the major metabolic effects of corticosteroids are mediated by changes in the key metabolic enzyme adenosine monophosphate-activated protein kinase (AMPK) activity. Activation of AMPK is known to stimulate appetite in the hypothalamus and stimulate catabolic processes in the periphery. We assessed AMPK activity and the expression of several metabolic enzymes in the hypothalamus, liver, adipose tissue, and heart of a rat glucocorticoid-excess model as well as in in vitro studies using primary human adipose and primary rat hypothalamic cell cultures, and a human hepatoma cell line treated with dexamethasone and metformin. Glucocorticoid treatment inhibited AMPK activity in rat adipose tissue and heart, while stimulating it in the liver and hypothalamus. Similar data were observed in vitro in the primary adipose and hypothalamic cells and in the liver cell line. Metformin, a known AMPK regulator, prevented the corticosteroid-induced effects on AMPK in human adipocytes and rat hypothalamic neurons. Our data suggest that glucocorticoid-induced changes in AMPK constitute a novel mechanism that could explain the increase in appetite, the deposition of lipids in visceral adipose and hepatic tissue, as well as the cardiac changes that are all characteristic of glucocorticoid excess. Our data suggest that metformin treatment could be effective in preventing the metabolic complications of chronic glucocorticoid excess.
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Affiliation(s)
- Mirjam Christ-Crain
- Department of Endocrinology, William Harvey Research Institute, Barts and the London, Queen Mary's School of Medicine, London EC1M 6BQ, UK
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Tiley HA, Geor RJ, McCutcheon LJ. Effects of dexamethasone administration on insulin resistance and components of insulin signaling and glucose metabolism in equine skeletal muscle. Am J Vet Res 2008; 69:51-8. [DOI: 10.2460/ajvr.69.1.51] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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