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Zhu Y, Liu W, Qi Z. Adipose tissue browning and thermogenesis under physiologically energetic challenges: a remodelled thermogenic system. J Physiol 2024; 602:23-48. [PMID: 38019069 DOI: 10.1113/jp285269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 11/16/2023] [Indexed: 11/30/2023] Open
Abstract
Metabolic diseases such as obesity and diabetes are often thought to be caused by reduced energy expenditure, which poses a serious threat to human health. Cold exposure, exercise and caloric restriction have been shown to promote adipose tissue browning and thermogenesis. These physiological interventions increase energy expenditure and thus have emerged as promising strategies for mitigating metabolic disorders. However, that increased adipose tissue browning and thermogenesis elevate thermogenic consumption is not a reasonable explanation when humans and animals confront energetic challenges imposed by these interventions. In this review, we collected numerous results on adipose tissue browning and whitening and evaluated this bi-directional conversion of adipocytes from the perspective of energy homeostasis. Here, we propose a new interpretation of the role of adipose tissue browning under energetic challenges: increased adipose tissue browning and thermogenesis under energy challenge is not to enhance energy expenditure, but to reestablish a more economical thermogenic pattern to maintain the core body temperature. This can be achieved by enhancing the contribution of non-shivering thermogenesis (adipose tissue browning and thermogenesis) and lowering shivering thermogenesis and high intensity shivering. Consequently, the proportion of heat production in fat increases and that in skeletal muscle decreases, enabling skeletal muscle to devote more energy reserves to overcoming environmental stress.
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Affiliation(s)
- Yupeng Zhu
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, China
- School of Physical Education and Health, East China Normal University, Shanghai, China
- Sino-French Joint Research Center of Sport Science, East China Normal University, Shanghai, China
| | - Weina Liu
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, China
- School of Physical Education and Health, East China Normal University, Shanghai, China
| | - Zhengtang Qi
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, China
- School of Physical Education and Health, East China Normal University, Shanghai, China
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Domínguez-Oliva A, Hernández-Ávalos I, Olmos-Hernández A, Villegas-Juache J, Verduzco-Mendoza A, Mota-Rojas D. Thermal Response of Laboratory Rats ( Rattus norvegicus) during the Application of Six Methods of Euthanasia Assessed by Infrared Thermography. Animals (Basel) 2023; 13:2820. [PMID: 37760220 PMCID: PMC10526081 DOI: 10.3390/ani13182820] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/28/2023] [Accepted: 09/01/2023] [Indexed: 09/29/2023] Open
Abstract
Refinement is one of the principles aiming to promote welfare in research animals. The techniques used during an experimental protocol, including euthanasia selection, must prevent and minimize suffering. Although the current euthanasia methods applied to laboratory rodents are accepted, the controversial findings regarding the potential stress/distress they can cause is a field of research. The objective was to assess the thermal response of Wistar rats during various euthanasia methods using infrared thermography (IRT) to determine the method that prevents or diminishes the stress response and prolonged suffering. Pentobarbital (G1), CO2 (G2), decapitation (G3), isoflurane (G4), ketamine + xylazine (G5), and ketamine + CO2 (G6) were evaluated at five evaluation times with IRT to identify changes in the surface temperature of four anatomical regions: ocular (T°ocu), auricular (T°ear), interscapular (T°dor), and caudal (T°tai). Significant differences (p < 0.05) were found in G2 and G4, registering temperature increases from the administration of the drug to the cessation of respiratory rate and heart rate. Particularly, isoflurane showed a marked thermal response in T°ocu, T°ear, T°dor, and T°tai, suggesting that, in general, inhalant euthanasia methods induce stress in rats and that isoflurane might potentially cause distress, an effect that must be considered when deciding humane euthanasia methods in laboratory rodents.
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Affiliation(s)
- Adriana Domínguez-Oliva
- Master in Science Program “Maestría en Ciencias Agropecuarias”, Xochimilco Campus, Universidad Autónoma Metropolitana, Mexico City 04960, Mexico
- Neurophysiology of Pain, Behavior and Assessment of Welfare in Domestic Animals, DPAA, Xochimilco Campus, Universidad Autónoma Metropolitana (UAM), Mexico City 04960, Mexico
| | - Ismael Hernández-Ávalos
- Clinical Pharmacology and Veterinary Anesthesia, Biological Sciences Department, Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, Cuautitlán Izcalli 54714, Mexico
| | - Adriana Olmos-Hernández
- Division of Biotechnology—Bioterio and Experimental Surgery, Instituto Nacional de Rehabilitación-Luis Guillermo Ibarra Ibarra (INR-LGII), Mexico City 14389, Mexico
| | - Juan Villegas-Juache
- Bioterio and Experimental Surgery, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City 14080, Mexico
| | - Antonio Verduzco-Mendoza
- Division of Biotechnology—Bioterio and Experimental Surgery, Instituto Nacional de Rehabilitación-Luis Guillermo Ibarra Ibarra (INR-LGII), Mexico City 14389, Mexico
| | - Daniel Mota-Rojas
- Neurophysiology of Pain, Behavior and Assessment of Welfare in Domestic Animals, DPAA, Xochimilco Campus, Universidad Autónoma Metropolitana (UAM), Mexico City 04960, Mexico
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3
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Martín FM, Alzamendi A, Harnichar AE, Castrogiovanni D, Zubiría MG, Spinedi E, Giovambattista A. Role of glucocorticoid receptor (GR) in white adipose tissue beiging. Life Sci 2023; 322:121681. [PMID: 37040814 DOI: 10.1016/j.lfs.2023.121681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 01/27/2023] [Accepted: 04/04/2023] [Indexed: 04/13/2023]
Abstract
AIM Glucocorticoids (GCs) play a crucial role in energy homeostasis including white adipose tissue function; however, chronic GC excess is detrimental to mammals' health. White hypertrophic adiposity is a main factor for neuroendocrine-metabolic dysfunctions in monosodium L-glutamate (MSG)-damaged hypercorticosteronemic rat. Nevertheless, little is known about the receptor path in endogenous GC impact on white adipose tissue-resident precursor cells to bring them into beige lineage. Thus, our aim was to explore whether transient/chronic endogenous hypercorticosteronemia affects browning capacity in white adipose tissue pads from MSG rats during development. MAIN METHODS Control and MSG male rats aged 30 and 90 days were 7-day exposed to cold conditions in order to stimulate wet white epidydimal adipose tissue (wEAT) beiging capacity. This procedure was also replicated in adrenalectomized rats. KEY FINDINGS Data indicated that whereas epidydimal white adipose tissue pads from prepubertal hypercorticosteronemic rats retained full expression of GR/MR genes resulting in a drastic reduction in wEAT beiging capacity, conversely, chronic hypercorticosteronemic adult MSG rats developed down-regulation of corticoid genes (and reduced GR cytosolic mediators) in wEAT pads and consequently partially restored local beiging capacity. Finally, wEAT pads from adrenalectomized rats revealed up-regulation of GR gene accompanied by full local beiging capacity. SIGNIFICANCE This study strongly supports a GR-dependent inhibitory effect of GC excess on white adipose tissue browning, an issue strongly supporting a key role of GR in the non-shivering thermogenic process. As a consequence, normalizing the GC milieu could be a relevant factor to handle dysmetabolism in white hyperadipose phenotypes.
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Affiliation(s)
- Florencia M Martín
- Centro de Endocrinología Experimental y Aplicada (CENEXA, UNLP-CONICET-CICPBA-CA), Facultad de Ciencias Médicas, Universidad Nacional de La Plata, 1900 La Plata, Argentina; Laboratorio de Neuroendocrinología, Instituto Multidisciplinario de Biología Celular (IMBICE, CICPBA-CONICET-UNLP), 1900 La Plata, Argentina
| | - Ana Alzamendi
- Laboratorio de Neuroendocrinología, Instituto Multidisciplinario de Biología Celular (IMBICE, CICPBA-CONICET-UNLP), 1900 La Plata, Argentina
| | - Alejandro E Harnichar
- Laboratorio de Neuroendocrinología, Instituto Multidisciplinario de Biología Celular (IMBICE, CICPBA-CONICET-UNLP), 1900 La Plata, Argentina
| | - Daniel Castrogiovanni
- Laboratorio de Neuroendocrinología, Instituto Multidisciplinario de Biología Celular (IMBICE, CICPBA-CONICET-UNLP), 1900 La Plata, Argentina
| | - María Guillermina Zubiría
- Laboratorio de Neuroendocrinología, Instituto Multidisciplinario de Biología Celular (IMBICE, CICPBA-CONICET-UNLP), 1900 La Plata, Argentina
| | - Eduardo Spinedi
- Centro de Endocrinología Experimental y Aplicada (CENEXA, UNLP-CONICET-CICPBA-CA), Facultad de Ciencias Médicas, Universidad Nacional de La Plata, 1900 La Plata, Argentina.
| | - Andrés Giovambattista
- Laboratorio de Neuroendocrinología, Instituto Multidisciplinario de Biología Celular (IMBICE, CICPBA-CONICET-UNLP), 1900 La Plata, Argentina
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Abstract
Brown adipose tissue (BAT) displays the unique capacity to generate heat through uncoupled oxidative phosphorylation that makes it a very attractive therapeutic target for cardiometabolic diseases. Here, we review BAT cellular metabolism, its regulation by the central nervous and endocrine systems and circulating metabolites, the plausible roles of this tissue in human thermoregulation, energy balance, and cardiometabolic disorders, and the current knowledge on its pharmacological stimulation in humans. The current definition and measurement of BAT in human studies relies almost exclusively on BAT glucose uptake from positron emission tomography with 18F-fluorodeoxiglucose, which can be dissociated from BAT thermogenic activity, as for example in insulin-resistant states. The most important energy substrate for BAT thermogenesis is its intracellular fatty acid content mobilized from sympathetic stimulation of intracellular triglyceride lipolysis. This lipolytic BAT response is intertwined with that of white adipose (WAT) and other metabolic tissues, and cannot be independently stimulated with the drugs tested thus far. BAT is an interesting and biologically plausible target that has yet to be fully and selectively activated to increase the body's thermogenic response and shift energy balance. The field of human BAT research is in need of methods able to directly, specifically, and reliably measure BAT thermogenic capacity while also tracking the related thermogenic responses in WAT and other tissues. Until this is achieved, uncertainty will remain about the role played by this fascinating tissue in human cardiometabolic diseases.
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Affiliation(s)
- André C Carpentier
- Correspondence: André C. Carpentier, MD, Division of Endocrinology, Faculty of Medicine, University of Sherbrooke, 3001, 12th Ave N, Sherbrooke, Quebec, J1H 5N4, Canada.
| | - Denis P Blondin
- Division of Neurology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, J1H 5N4, Canada
| | | | - Denis Richard
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Quebec City, Quebec, G1V 4G5, Canada
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5
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de Winne C, Pascual FL, Lopez-Vicchi F, Etcheverry-Boneo L, Mendez-Garcia LF, Ornstein AM, Lacau-Mengido IM, Sorianello E, Becu-Villalobos D. Neuroendocrine control of brown adipocyte function by prolactin and growth hormone. J Neuroendocrinol 2023:e13248. [PMID: 36932836 DOI: 10.1111/jne.13248] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 02/08/2023] [Accepted: 02/11/2023] [Indexed: 03/06/2023]
Abstract
Growth hormone (GH) is fundamental for growth and glucose homeostasis, and prolactin for optimal pregnancy and lactation outcome, but additionally, both hormones have multiple functions that include a strong impact on energetic metabolism. In this respect, prolactin and GH receptors have been found in brown, and white adipocytes, as well as in hypothalamic centers regulating thermogenesis. This review describes the neuroendocrine control of the function and plasticity of brown and beige adipocytes, with a special focus on prolactin and GH actions. Most evidence points to a negative association between high prolactin levels and the thermogenic capacity of BAT, except in early development. During lactation and pregnancy, prolactin may be a contributing factor that limits unneeded thermogenesis, downregulating BAT UCP1. Furthermore, animal models of high serum prolactin have low BAT UCP1 levels and whitening of the tissue, while lack of Prlr induces beiging in WAT depots. These actions may involve hypothalamic nuclei, particularly the DMN, POA and ARN, brain centers that participate in thermogenesis. Studies on GH regulation of BAT function present some controversies. Most mouse models with GH excess or deficiency point to an inhibitory role of GH on BAT function. Even so, a stimulatory role of GH on WAT beiging has also been described, in accordance with whole-genome microarrays that demonstrate divergent response signatures of BAT and WAT genes to the loss of GH signaling. Understanding the physiology of BAT and WAT beiging may contribute to the ongoing efforts to curtail obesity.
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Affiliation(s)
- Catalina de Winne
- Instituto de Biología y Medicina Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad de Buenos Aires, Argentina
| | - Florencia L Pascual
- Instituto de Biología y Medicina Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad de Buenos Aires, Argentina
| | - Felicitas Lopez-Vicchi
- Instituto de Biología y Medicina Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad de Buenos Aires, Argentina
| | - Luz Etcheverry-Boneo
- Instituto de Biología y Medicina Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad de Buenos Aires, Argentina
| | - Luis F Mendez-Garcia
- Instituto de Biología y Medicina Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad de Buenos Aires, Argentina
| | - Ana Maria Ornstein
- Instituto de Biología y Medicina Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad de Buenos Aires, Argentina
| | - Isabel Maria Lacau-Mengido
- Instituto de Biología y Medicina Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad de Buenos Aires, Argentina
| | - Eleonora Sorianello
- Instituto de Biología y Medicina Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad de Buenos Aires, Argentina
| | - Damasia Becu-Villalobos
- Instituto de Biología y Medicina Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad de Buenos Aires, Argentina
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6
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Daskalakis E, Hassan MH, Omar AM, Acar AA, Fallah A, Cooper G, Weightman A, Blunn G, Koc B, Bartolo P. Accelerated Degradation of Poly-ε-caprolactone Composite Scaffolds for Large Bone Defects. Polymers (Basel) 2023; 15:polym15030670. [PMID: 36771970 PMCID: PMC9921763 DOI: 10.3390/polym15030670] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/13/2023] [Accepted: 01/21/2023] [Indexed: 01/31/2023] Open
Abstract
This research investigates the accelerated hydrolytic degradation process of both anatomically designed bone scaffolds with a pore size gradient and a rectangular shape (biomimetically designed scaffolds or bone bricks). The effect of material composition is investigated considering poly-ε-caprolactone (PCL) as the main scaffold material, reinforced with ceramics such as hydroxyapatite (HA), β-tricalcium phosphate (TCP) and bioglass at a concentration of 20 wt%. In the case of rectangular scaffolds, the effect of pore size (200 μm, 300 μm and 500 μm) is also investigated. The degradation process (accelerated degradation) was investigated during a period of 5 days in a sodium hydroxide (NaOH) medium. Degraded bone bricks and rectangular scaffolds were measured each day to evaluate the weight loss of the samples, which were also morphologically, thermally, chemically and mechanically assessed. The results show that the PCL/bioglass bone brick scaffolds exhibited faster degradation kinetics in comparison with the PCL, PCL/HA and PCL/TCP bone bricks. Furthermore, the degradation kinetics of rectangular scaffolds increased by increasing the pore size from 500 μm to 200 μm. The results also indicate that, for the same material composition, bone bricks degrade slower compared with rectangular scaffolds. The scanning electron microscopy (SEM) images show that the degradation process was faster on the external regions of the bone brick scaffolds (600 μm pore size) compared with the internal regions (200 μm pore size). The thermal gravimetric analysis (TGA) results show that the ceramic concentration remained constant throughout the degradation process, while differential scanning calorimetry (DSC) results show that all scaffolds exhibited a reduction in crystallinity (Xc), enthalpy (Δm) and melting temperature (Tm) throughout the degradation process, while the glass transition temperature (Tg) slightly increased. Finally, the compression results show that the mechanical properties decreased during the degradation process, with PCL/bioglass bone bricks and rectangular scaffolds presenting higher mechanical properties with the same design in comparison with the other materials.
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Affiliation(s)
- Evangelos Daskalakis
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester M13 9PL, UK
| | - Mohamed H Hassan
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester M13 9PL, UK
| | - Abdalla M Omar
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester M13 9PL, UK
| | - Anil A Acar
- Integrated Manufacturing Technologies Research and Application Center, Sabanci University, Tuzla 34956, Istanbul, Turkey
- SUNUM Nanotechnology Research Center, Sabanci University, Tuzla 34956, Istanbul, Turkey
- Faculty of Engineering and Natural Sciences, Sabanci University, Tuzla 34956, Istanbul, Turkey
| | - Ali Fallah
- Integrated Manufacturing Technologies Research and Application Center, Sabanci University, Tuzla 34956, Istanbul, Turkey
- SUNUM Nanotechnology Research Center, Sabanci University, Tuzla 34956, Istanbul, Turkey
- Faculty of Engineering and Natural Sciences, Sabanci University, Tuzla 34956, Istanbul, Turkey
| | - Glen Cooper
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester M13 9PL, UK
| | - Andrew Weightman
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester M13 9PL, UK
| | - Gordon Blunn
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DT, UK
| | - Bahattin Koc
- Integrated Manufacturing Technologies Research and Application Center, Sabanci University, Tuzla 34956, Istanbul, Turkey
- SUNUM Nanotechnology Research Center, Sabanci University, Tuzla 34956, Istanbul, Turkey
- Faculty of Engineering and Natural Sciences, Sabanci University, Tuzla 34956, Istanbul, Turkey
| | - Paulo Bartolo
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester M13 9PL, UK
- Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore
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Dexamethasone-Induced Adipose Tissue Redistribution and Metabolic Changes: Is Gene Expression the Main Factor? An Animal Model of Chronic Hypercortisolism. Biomedicines 2022; 10:biomedicines10092328. [PMID: 36140428 PMCID: PMC9496558 DOI: 10.3390/biomedicines10092328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/03/2022] [Accepted: 09/06/2022] [Indexed: 11/17/2022] Open
Abstract
Chronic hypercortisolism has been associated with the development of several metabolic alterations, mostly caused by the effects of chronic glucocorticoid (GC) exposure over gene expression. The metabolic changes can be partially explained by the GC actions on different adipose tissues (ATs), leading to central obesity. In this regard, we aimed to characterize an experimental model of iatrogenic hypercortisolism in rats with significant AT redistribution. Male Wistar rats were distributed into control (CT) and GC-treated, which received dexamethasone sodium phosphate (0.5 mg/kg/day) by an osmotic minipump, for 4 weeks. GC-treated rats reproduced several characteristics observed in human hypercortisolism/Cushing’s syndrome, such as HPA axis inhibition, glucose intolerance, insulin resistance, dyslipidemia, hepatic lipid accumulation, and AT redistribution. There was an increase in the mesenteric (meWAT), perirenal (prWAT), and interscapular brown (BAT) ATs mass, but a reduction of the retroperitoneal (rpWAT) mass compared to CT rats. Overexpressed lipolytic and lipogenic gene profiles were observed in white adipose tissue (WAT) of GC rats as BAT dysfunction and whitening. The AT remodeling in response to GC excess showed more importance than the increase of AT mass per se, and it cannot be explained just by GC regulation of gene transcription.
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8
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Assis AP, Silva KE, Lautherbach N, Morgan HJN, Garófalo MAR, Zanon NM, Navegantes LCC, Chaves VE, Kettelhut IDC. Glucocorticoids decrease thermogenic capacity and increase triacylglycerol synthesis by glycerokinase activation in the brown adipose tissue of rats. Lipids 2022; 57:313-325. [PMID: 36098349 DOI: 10.1002/lipd.12358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 08/03/2022] [Accepted: 08/28/2022] [Indexed: 11/11/2022]
Abstract
Although it is well established that glucocorticoids inactivate thermogenesis and promote lipid accumulation in interscapular brown adipose tissue (IBAT), the underlying mechanisms remain unknown. We found that dexamethasone treatment (1 mg/kg) for 7 days in rats decreased the IBAT thermogenic activity, evidenced by its lower responsiveness to noradrenaline injection associated with reduced content of mitochondrial proteins, respiratory chain protein complexes, noradrenaline, and the β3 -adrenergic receptor. In parallel, to understand better how dexamethasone increases IBAT lipid content, we also investigated the activity of the ATP citrate lyase (ACL), a key enzyme of de novo fatty acid synthesis, glucose-6-phosphate dehydrogenase (G6PD), a rate-limiting enzyme of the pentose phosphate pathway, and the three glycerol-3-P generating pathways: (1) glycolysis, estimated by 2-deoxyglucose uptake, (2) glyceroneogenesis, evaluated by phosphoenolpyruvate carboxykinase activity and pyruvate incorporation into triacylglycerol-glycerol, and (3) direct phosphorylation of glycerol, investigated by the content and activity of glycerokinase. Dexamethasone increased the mass and the lipid content of IBAT as well as plasma levels of glucose, insulin, non-esterified fatty acid, and glycerol. Furthermore, dexamethasone increased ACL and G6PD activities (79% and 48%, respectively). Despite promoting a decrease in the incorporation of U-[14 C]-glycerol into triacylglycerol (~54%), dexamethasone increased the content (~55%) and activity (~41%) of glycerokinase without affecting glucose uptake or glyceroneogenesis. Our data suggest that glucocorticoid administration reduces IBAT thermogenesis through sympathetic inactivation and stimulates glycerokinase activity and content, contributing to increased generation of glycerol-3-P, which is mostly used to esterify fatty acid and increase triacylglycerol content promoting IBAT whitening.
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Affiliation(s)
- Ana Paula Assis
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Karine Emanuelle Silva
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Natalia Lautherbach
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | | | | | - Neusa Maria Zanon
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | | | | | - Isis do Carmo Kettelhut
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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9
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Haque N, Tischkau SA. Sexual Dimorphism in Adipose-Hypothalamic Crosstalk and the Contribution of Aryl Hydrocarbon Receptor to Regulate Energy Homeostasis. Int J Mol Sci 2022; 23:ijms23147679. [PMID: 35887027 PMCID: PMC9322714 DOI: 10.3390/ijms23147679] [Citation(s) in RCA: 2] [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: 06/16/2022] [Revised: 07/08/2022] [Accepted: 07/09/2022] [Indexed: 11/16/2022] Open
Abstract
There are fundamental sex differences in the regulation of energy homeostasis. Better understanding of the underlying mechanisms of energy balance that account for this asymmetry will assist in developing sex-specific therapies for sexually dimorphic diseases such as obesity. Multiple organs, including the hypothalamus and adipose tissue, play vital roles in the regulation of energy homeostasis, which are regulated differently in males and females. Various neuronal populations, particularly within the hypothalamus, such as arcuate nucleus (ARC), can sense nutrient content of the body by the help of peripheral hormones such leptin, derived from adipocytes, to regulate energy homeostasis. This review summarizes how adipose tissue crosstalk with homeostatic network control systems in the brain, which includes energy regulatory regions and the hypothalamic–pituitary axis, contribute to energy regulation in a sex-specific manner. Moreover, development of obesity is contingent upon diet and environmental factors. Substances from diet and environmental contaminants can exert insidious effects on energy metabolism, acting peripherally through the aryl hydrocarbon receptor (AhR). Developmental AhR activation can impart permanent alterations of neuronal development that can manifest a number of sex-specific physiological changes, which sometimes become evident only in adulthood. AhR is currently being investigated as a potential target for treating obesity. The consensus is that impaired function of the receptor protects from obesity in mice. AhR also modulates sex steroid receptors, and hence, one of the objectives of this review is to explain why investigating sex differences while examining this receptor is crucial. Overall, this review summarizes sex differences in the regulation of energy homeostasis imparted by the adipose–hypothalamic axis and examines how this axis can be affected by xenobiotics that signal through AhR.
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Affiliation(s)
- Nazmul Haque
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL 62702, USA;
| | - Shelley A. Tischkau
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL 62702, USA;
- Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL 62702, USA
- Correspondence:
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10
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Bel JS, Tai TC, Khaper N, Lees SJ. Chronic glucocorticoid exposure causes brown adipose tissue whitening, alters whole-body glucose metabolism and increases tissue uncoupling protein-1. Physiol Rep 2022; 10:e15292. [PMID: 35510321 PMCID: PMC9069169 DOI: 10.14814/phy2.15292] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 04/05/2022] [Accepted: 04/11/2022] [Indexed: 04/14/2023] Open
Abstract
Adipose tissue (AT) has been found to exist in two predominant forms, white and brown. White adipose tissue (WAT) is the body's conventional storage organ, and brown adipose tissue (BAT) is responsible for non-shivering thermogenesis which allows mammals to produce heat and regulate body temperature. Studies examining BAT and its role in whole-body metabolism have found that active BAT utilizes glucose and circulating fatty acids and is associated with improved metabolic outcomes. While the beiging of WAT is a growing area of interest, the possibility of the BAT depot to "whiten" and store more triglycerides also has metabolic and health implications. Currently, there are limited studies that examine the effects of chronic stress and its ability to induce a white-like phenotype in the BAT depot. This research examined how chronic exposure to the murine stress hormone, corticosterone, for 4 weeks can affect the whitening process of BAT in C57BL/6 male mice. Separate treatments with mirabegron, a known β3-adrenergic receptor agonist, were used to directly compare the effects of corticosterone with a beiging phenotype. Corticosterone-treated mice had significantly higher body weight (p ≤ 0.05) and BAT mass (p ≤ 0.05), increased adipocyte area (p ≤ 0.05), were insulin resistant (p ≤ 0.05), and significantly elevated expressions of uncoupling protein 1 (UCP-1) in BAT (p ≤ 0.05) while mitochondrial content remained unchanged. This whitened phenotype has not been previously associated with increased uncoupling proteins under chronic stress and may represent a compensatory mechanism being initiated under these conditions. These findings have implications for the study of BAT in response to chronic glucocorticoid exposure potentially leading to BAT dysfunction and negative impacts on whole-body glucose metabolism.
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Affiliation(s)
- Jocelyn S. Bel
- Biotechnology ProgramLakehead UniversityThunder BayOntarioCanada
| | - T. C. Tai
- Northern Ontario School of MedicineThunder BayOntarioCanada
- BiologyLaurentian UniversitySudburyOntarioCanada
- Chemistry and BiochemistryLaurentian UniversitySudburyOntarioCanada
- Biomolecular Sciences ProgramLaurentian UniversitySudburyOntarioCanada
| | - Neelam Khaper
- Northern Ontario School of MedicineThunder BayOntarioCanada
- Biomolecular Sciences ProgramLaurentian UniversitySudburyOntarioCanada
- BiologyLakehead UniversityThunder BayOntarioCanada
| | - Simon J. Lees
- Northern Ontario School of MedicineThunder BayOntarioCanada
- BiologyLakehead UniversityThunder BayOntarioCanada
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11
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Countering obesity with eosinophils and sympathetic fat. Proc Natl Acad Sci U S A 2022; 119:2123084119. [PMID: 35105817 PMCID: PMC8833142 DOI: 10.1073/pnas.2123084119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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12
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de Souza JA, da Silva MC, de Souza Ferraz Junior JC, de Souza FL, de Souza SL. Maternal separation in the light or dark phase of the circadian cycle has different effects on the corticosterone levels and anxiety-like behavior in male adult rats. Physiol Behav 2022; 247:113725. [DOI: 10.1016/j.physbeh.2022.113725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/19/2022] [Accepted: 01/28/2022] [Indexed: 11/26/2022]
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13
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Yudasaka M, Okamatsu-Ogura Y, Tanaka T, Saeki K, Kataura H. Cold-induced Conversion of Connective Tissue Skeleton in Brown Adipose Tissues. Acta Histochem Cytochem 2021; 54:131-141. [PMID: 34764522 PMCID: PMC8569133 DOI: 10.1267/ahc.21-00030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/28/2021] [Indexed: 01/21/2023] Open
Abstract
Thermogenesis via fatty acid-induced uncoupled mitochondrial respiration is the primary function of brown adipose tissue (BAT). In response to changes in ambient temperatures, the weight and specific gravity of BAT change, depending on the quantity of lipid droplets stored in brown adipocytes (BA). Such conditions should result in the reconstruction of connective tissue skeletons, especially of collagen fiber networks, although the mechanisms have not been clarified. This study showed that, within 4 hr of exposing mice to a cold environment, collagen fibers in the extracellular matrix (ECM) of BAT became discontinuous, twisted, emancipated, and curtailed. Surprisingly, the structure of collagen fibers returned to normal after the mice were kept at room temperature for 19 hr, indicating that the alterations in collagen fiber structures are physiological processes association with adaptation to cold environments. These dynamic changes in connective tissue skeletons were not observed in white adipose tissues, suggesting that they are unique to BAT. Interestingly, the vascular permeability of BAT was also augmented by exposure to cold. Collectively, these findings indicate that dynamic changes in ECM collagen fibers provide high flexibility to BAT, enabling the adjustment of tissue structures and the regulation of vascular permeability, resulting in adaptation to changes in ambient temperatures.
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Affiliation(s)
- Masako Yudasaka
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology
| | - Yuko Okamatsu-Ogura
- Laboratory of Biochemistry, Faculty of Veterinary Medicine, Hokkaido University
| | - Takeshi Tanaka
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology
| | - Kumiko Saeki
- Department of Laboratory Molecular Genetics of Hematology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Hiromichi Kataura
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology
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14
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Genomic and Non-Genomic Actions of Glucocorticoids on Adipose Tissue Lipid Metabolism. Int J Mol Sci 2021; 22:ijms22168503. [PMID: 34445209 PMCID: PMC8395154 DOI: 10.3390/ijms22168503] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/01/2021] [Accepted: 08/04/2021] [Indexed: 12/15/2022] Open
Abstract
Glucocorticoids (GCs) are hormones that aid the body under stress by regulating glucose and free fatty acids. GCs maintain energy homeostasis in multiple tissues, including those in the liver and skeletal muscle, white adipose tissue (WAT), and brown adipose tissue (BAT). WAT stores energy as triglycerides, while BAT uses fatty acids for heat generation. The multiple genomic and non-genomic pathways in GC signaling vary with exposure duration, location (adipose tissue depot), and species. Genomic effects occur directly through the cytosolic GC receptor (GR), regulating the expression of proteins related to lipid metabolism, such as ATGL and HSL. Non-genomic effects act through mechanisms often independent of the cytosolic GR and happen shortly after GC exposure. Studying the effects of GCs on adipose tissue breakdown and generation (lipolysis and adipogenesis) leads to insights for treatment of adipose-related diseases, such as obesity, coronary disease, and cancer, but has led to controversy among researchers, largely due to the complexity of the process. This paper reviews the recent literature on the genomic and non-genomic effects of GCs on WAT and BAT lipolysis and proposes research to address the many gaps in knowledge related to GC activity and its effects on disease.
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15
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A physiological glucocorticoid rhythm is an important regulator of brown adipose tissue function. Mol Metab 2021; 47:101179. [PMID: 33548499 PMCID: PMC7907824 DOI: 10.1016/j.molmet.2021.101179] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/27/2021] [Accepted: 01/29/2021] [Indexed: 12/18/2022] Open
Abstract
Objective Brown adipose tissue (BAT) displays a strong circadian rhythm in metabolic activity, but it is unclear how this rhythm is regulated. As circulating levels of corticosterone coincide with the rhythm of triglyceride-derived fatty acid (FA) uptake by BAT, we investigated whether corticosterone regulates BAT circadian rhythm. Methods Corticosterone levels were flattened by implanting mice with subcutaneous corticosterone-releasing pellets, resulting in constant circulating corticosterone levels. Results Flattened corticosterone rhythm caused a complete loss of circadian rhythm in triglyceride-derived fatty acid uptake by BAT. This effect was independent of glucocorticoid receptor expression in (brown) adipocytes and was not caused by deregulation of clock gene expression or overexposure to glucocorticoids, but rather seemed mediated by reduced sympathetic innervation of BAT. In a mouse model of hyperlipidemia and metabolic syndrome, long-term experimental flattening of corticosterone − and thus rhythm in BAT function − resulted in adiposity. Conclusions This study highlights that a physiological rhythm in glucocorticoids is an important regulator of BAT function and essential for the maintenance of metabolic health. Flattening of corticosterone rhythm blunts circadian activity of brown adipose tissue. Disturbed corticosterone rhythm − rather than overexposure− is responsible for blunted brown adipose tissue activity. The metabolic effect of flattened corticosterone levels is independent of adipocyte glucocorticoid receptor expression. Long-term flattening of corticosterone levels results in increased adiposity in a female mouse model for metabolic syndrome.
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16
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Kaikaew K, Grefhorst A, Visser JA. Sex Differences in Brown Adipose Tissue Function: Sex Hormones, Glucocorticoids, and Their Crosstalk. Front Endocrinol (Lausanne) 2021; 12:652444. [PMID: 33927694 PMCID: PMC8078866 DOI: 10.3389/fendo.2021.652444] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/23/2021] [Indexed: 12/12/2022] Open
Abstract
Excessive fat accumulation in the body causes overweight and obesity. To date, research has confirmed that there are two types of adipose tissue with opposing functions: lipid-storing white adipose tissue (WAT) and lipid-burning brown adipose tissue (BAT). After the rediscovery of the presence of metabolically active BAT in adults, BAT has received increasing attention especially since activation of BAT is considered a promising way to combat obesity and associated comorbidities. It has become clear that energy homeostasis differs between the sexes, which has a significant impact on the development of pathological conditions such as type 2 diabetes. Sex differences in BAT activity may contribute to this and, therefore, it is important to address the underlying mechanisms that contribute to sex differences in BAT activity. In this review, we discuss the role of sex hormones in the regulation of BAT activity under physiological and some pathological conditions. Given the increasing number of studies suggesting a crosstalk between sex hormones and the hypothalamic-pituitary-adrenal axis in metabolism, we also discuss this crosstalk in relation to sex differences in BAT activity.
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Affiliation(s)
- Kasiphak Kaikaew
- Department of Physiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Aldo Grefhorst
- Department of Experimental Vascular Medicine, Amsterdam University Medical Centers, Location AMC, Amsterdam, Netherlands
| | - Jenny A. Visser
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
- *Correspondence: Jenny A. Visser,
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17
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Kroon J, Pereira AM, Meijer OC. Glucocorticoid Sexual Dimorphism in Metabolism: Dissecting the Role of Sex Hormones. Trends Endocrinol Metab 2020; 31:357-367. [PMID: 32037025 DOI: 10.1016/j.tem.2020.01.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 12/20/2019] [Accepted: 01/13/2020] [Indexed: 12/15/2022]
Abstract
Glucocorticoids are steroid hormones that are of pivotal importance in human physiology. Glucocorticoid signaling is complex in nature and dependent on many interacting factors. As glucocorticoids exhibit sexually dimorphic effects on several key processes including in metabolism, crosstalk with the sex steroid hormones (androgens and estrogens) is relevant. In this review, we highlight the state-of-the-art knowledge on glucocorticoid sexual dimorphism and sex hormone crosstalk. We include current insight in the molecular mechanisms that underlie nuclear steroid receptor crosstalk, and sex hormone effects on glucocorticoid metabolism. Finally, we show how these findings translate to humans exposed to excess glucocorticoid signaling, and we propose future avenues in the emerging field of steroid hormone crosstalk.
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Affiliation(s)
- Jan Kroon
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, Leiden, The Netherlands; Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands.
| | - Alberto M Pereira
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, Leiden, The Netherlands; Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Onno C Meijer
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, Leiden, The Netherlands; Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
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18
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Luijten IHN, Cannon B, Nedergaard J. Glucocorticoids and Brown Adipose Tissue: Do glucocorticoids really inhibit thermogenesis? Mol Aspects Med 2019; 68:42-59. [PMID: 31323252 DOI: 10.1016/j.mam.2019.07.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 07/11/2019] [Indexed: 12/13/2022]
Abstract
A reduction in the thermogenic activity of brown adipose tissue (BAT) is presently discussed as a possible determinant for the development of obesity in humans. One group of endogenous factors that could potentially affect BAT activity is the glucocorticoids (e.g. cortisol). We analyse here studies examining the effects of alterations in glucocorticoid signaling on BAT recruitment and thermogenic capacity. We find that irrespective of which manipulation of glucocorticoid signaling is examined, a seemingly homogeneous picture of lowered thermogenic capacity due to glucocorticoid stimulation is apparently obtained: e.g. lowered uncoupling protein 1 (UCP1) protein levels per mg protein, and an increased lipid accumulation in BAT. However, further analyses generally indicate that these effects result from a dilution effect rather than a true decrease in total capacity; the tissue may thus be said to be in a state of pseudo-atrophy. However, under conditions of very low physiological stimulation of BAT, glucocorticoids may truly inhibit Ucp1 gene expression and consequently lower total UCP1 protein levels, but the metabolic effects of this reduction are probably minor. It is thus unlikely that glucocorticoids affect organismal metabolism and induce the development of obesity through alterations of BAT activity.
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Affiliation(s)
- Ineke H N Luijten
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Barbara Cannon
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Jan Nedergaard
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.
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