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Prapaharan B, Lea M, Beaudry JL. Weighing in on the role of brown adipose tissue for treatment of obesity. JOURNAL OF PHARMACY & PHARMACEUTICAL SCIENCES : A PUBLICATION OF THE CANADIAN SOCIETY FOR PHARMACEUTICAL SCIENCES, SOCIETE CANADIENNE DES SCIENCES PHARMACEUTIQUES 2024; 27:13157. [PMID: 39087083 PMCID: PMC11290130 DOI: 10.3389/jpps.2024.13157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Accepted: 07/01/2024] [Indexed: 08/02/2024]
Abstract
Brown adipose tissue (BAT) activation is an emerging target for obesity treatments due to its thermogenic properties stemming from its ability to shuttle energy through uncoupling protein 1 (Ucp1). Recent rodent studies show how BAT and white adipose tissue (WAT) activity can be modulated to increase the expression of thermogenic proteins. Consequently, these alterations enable organisms to endure cold-temperatures and elevate energy expenditure, thereby promoting weight loss. In humans, BAT is less abundant in obese subjects and impacts of thermogenesis are less pronounced, bringing into question whether energy expending properties of BAT seen in rodents can be translated to human models. Our review will discuss pharmacological, hormonal, bioactive, sex-specific and environmental activators and inhibitors of BAT to determine the potential for BAT to act as a therapeutic strategy. We aim to address the feasibility of utilizing BAT modulators for weight reduction in obese individuals, as recent studies suggest that BAT's contributions to energy expenditure along with Ucp1-dependent and -independent pathways may or may not rectify energy imbalance characteristic of obesity.
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Affiliation(s)
| | | | - Jacqueline L. Beaudry
- Temerty Faculty of Medicine, Department of Nutritional Sciences, University of Toronto, Toronto, ON, Canada
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2
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Mukaida S, Sato M, Öberg AI, Dehvari N, Olsen JM, Kocan M, Halls ML, Merlin J, Sandström AL, Csikasz RI, Evans BA, Summers RJ, Hutchinson DS, Bengtsson T. BRL37344 stimulates GLUT4 translocation and glucose uptake in skeletal muscle via β 2-adrenoceptors without causing classical receptor desensitization. Am J Physiol Regul Integr Comp Physiol 2019; 316:R666-R677. [PMID: 30892909 DOI: 10.1152/ajpregu.00285.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The type 2 diabetes epidemic makes it important to find insulin-independent ways to improve glucose homeostasis. This study examines the mechanisms activated by a dual β2-/β3-adrenoceptor agonist, BRL37344, to increase glucose uptake in skeletal muscle and its effects on glucose homeostasis in vivo. We measured the effect of BRL37344 on glucose uptake, glucose transporter 4 (GLUT4) translocation, cAMP levels, β2-adrenoceptor desensitization, β-arrestin recruitment, Akt, AMPK, and mammalian target of rapamycin (mTOR) phosphorylation using L6 skeletal muscle cells as a model. We further tested the ability of BRL37344 to modulate skeletal muscle glucose metabolism in animal models (glucose tolerance tests and in vivo and ex vivo skeletal muscle glucose uptake). In L6 cells, BRL37344 increased GLUT4 translocation and glucose uptake only by activation of β2-adrenoceptors, with a similar potency and efficacy to that of the nonselective β-adrenoceptor agonist isoprenaline, despite being a partial agonist with respect to cAMP generation. GLUT4 translocation occurred independently of Akt and AMPK phosphorylation but was dependent on mTORC2. Furthermore, in contrast to isoprenaline, BRL37344 did not promote agonist-mediated desensitization and failed to recruit β-arrestin1/2 to the β2-adrenoceptor. In conclusion, BRL37344 improved glucose tolerance and increased glucose uptake into skeletal muscle in vivo and ex vivo through a β2-adrenoceptor-mediated mechanism independently of Akt. BRL37344 was a partial agonist with respect to cAMP, but a full agonist for glucose uptake, and importantly did not cause classical receptor desensitization or internalization of the receptor.
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Affiliation(s)
- Saori Mukaida
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria , Australia
| | - Masaaki Sato
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria , Australia
| | - Anette I Öberg
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University , Stockholm , Sweden
| | - Nodi Dehvari
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University , Stockholm , Sweden
| | - Jessica M Olsen
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University , Stockholm , Sweden
| | - Martina Kocan
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria , Australia
| | - Michelle Louise Halls
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria , Australia
| | - Jon Merlin
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria , Australia
| | - Anna L Sandström
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University , Stockholm , Sweden
| | - Robert I Csikasz
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University , Stockholm , Sweden
| | - Bronwyn Anne Evans
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria , Australia
| | - Roger James Summers
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria , Australia.,Department of Pharmacology, Monash University , Clayton, Victoria , Australia
| | - Dana Sabine Hutchinson
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria , Australia.,Department of Pharmacology, Monash University , Clayton, Victoria , Australia
| | - Tore Bengtsson
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University , Stockholm , Sweden
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3
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Muhammad AB, Lokhandwala MF, Banday AA. Exercise reduces oxidative stress but does not alleviate hyperinsulinemia or renal dopamine D1 receptor dysfunction in obese rats. Am J Physiol Renal Physiol 2010; 300:F98-104. [PMID: 20926629 DOI: 10.1152/ajprenal.00386.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Impairment of renal dopamine D1 receptor (D1R)-mediated natriuresis is associated with hypertension in humans and animal models, including obese Zucker rats. We have previously reported that treatment of these rats with antioxidants or insulin sensitizers reduced insulin levels and oxidative stress, restored D1R-mediated natriuresis, and reduced blood pressure. Furthermore, the redox-sensitive transcription factor, nuclear factor-κB (NF-κB), has been implicated in impairment of D1R-mediated natriuresis during oxidative stress. In this study, we investigated the effect of exercise on insulin levels, oxidative stress, nuclear translocation of NF-κB, blood pressure, albuminuria, and D1R-mediated natriuresis. The exercise protocol involved treadmill exercise from 3 wk of age for 8 wk. Exercise reduced oxidative stress, nuclear translocation of NF-κB, and albuminuria. However, exercise did not reduce plasma insulin levels or blood pressure. Also, selective D1R agonist (SKF-38393)-mediated increases in sodium excretion and guanosine 5'-O-(3-thiotriphosphate) binding were impaired in obese rats compared with lean rats, and exercise did not restore this defect. We conclude that, while exercise is beneficial in reducing oxidative stress and renal injury, reducing insulin levels may be required to restore D1R-mediated natriuresis in this model of obesity and metabolic syndrome. Furthermore, this study supports previous observations that restoring D1R function contributes to blood pressure reduction in this model.
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Affiliation(s)
- Abdul Bari Muhammad
- Heart and Kidney Institute, College of Pharmacy, S & R-2 Bldg, University of Houston, 4800 Calhoun Rd., Houston, TX 77204, USA
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4
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Ropelle ER, Fernandes MFA, Flores MBS, Ueno M, Rocco S, Marin R, Cintra DE, Velloso LA, Franchini KG, Saad MJA, Carvalheira JBC. Central exercise action increases the AMPK and mTOR response to leptin. PLoS One 2008; 3:e3856. [PMID: 19052642 PMCID: PMC2585815 DOI: 10.1371/journal.pone.0003856] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Accepted: 11/06/2008] [Indexed: 11/19/2022] Open
Abstract
AMP-activated protein kinase (AMPK) and mammalian Target of Rapamycin (mTOR) are key regulators of cellular energy balance and of the effects of leptin on food intake. Acute exercise is associated with increased sensitivity to the effects of leptin on food intake in an IL-6-dependent manner. To determine whether exercise ameliorates the AMPK and mTOR response to leptin in the hypothalamus in an IL-6-dependent manner, rats performed two 3-h exercise bouts, separated by one 45-min rest period. Intracerebroventricular IL-6 infusion reduced food intake and pretreatment with AMPK activators and mTOR inhibitor prevented IL-6-induced anorexia. Activators of AMPK and fasting increased food intake in control rats to a greater extent than that observed in exercised ones, whereas inhibitor of AMPK had the opposite effect. Furthermore, the reduction of AMPK and ACC phosphorylation and increase in phosphorylation of proteins involved in mTOR signal transduction, observed in the hypothalamus after leptin infusion, were more pronounced in both lean and diet-induced obesity rats after acute exercise. Treatment with leptin reduced food intake in exercised rats that were pretreated with vehicle, although no increase in responsiveness to leptin-induced anorexia after pretreatment with anti-IL6 antibody, AICAR or Rapamycin was detected. Thus, the effects of leptin on the AMPK/mTOR pathway, potentiated by acute exercise, may contribute to appetite suppressive actions in the hypothalamus.
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Affiliation(s)
- Eduardo R. Ropelle
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | | | - Marcelo B. S. Flores
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Mirian Ueno
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Silvana Rocco
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Rodrigo Marin
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Dennys E. Cintra
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Lício A. Velloso
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Kleber G. Franchini
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Mario J. A. Saad
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - José B. C. Carvalheira
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
- * E-mail:
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5
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Urano Y, Sakurai T, Ueda H, Ogasawara J, Sakurai T, Takei M, Izawa T. Desensitization of the inhibitory effect of norepinephrine on insulin secretion from pancreatic islets of exercise-trained rats. Metabolism 2004; 53:1424-32. [PMID: 15536596 DOI: 10.1016/j.metabol.2004.06.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effect of exercise training (9 weeks of running) on norepinephrine-induced inhibition of insulin secretion was examined in rat islets. Insulin secretions from islets in the presence of glucose (> or =5.5 mmol/L) were significantly lower in trained (TR) than in control rats (CR). Norepinephrine inhibited 5.5 mmol/L glucose-stimulated insulin secretions and cyclic adenosine monophosphate (cAMP) contents in a dose-dependent manner in CR. Norepinephrine (10 micromol/L)-induced inhibition of insulin secretion was reversed by the blockade of the alpha(2)-adrenergic receptor in CR, but not in TR. Exercise training substantially shifted the dose-dependent curve for clonidine-induced inhibition of insulin secretions and that of cAMP contents to the right. Exercise training did not alter the density of the alpha(2)-adrenergic receptor either per islet or per protein of islet crude membrane. However, exercise training significantly reduced the protein expression of G alpha i-2 without change in G alpha i-2 mRNA. In CR but not in TR, norepinephrine significantly inhibited insulin secretions elicited by a combination of high glucose, a protein kinase C activator, and an adenylate cyclase activator under Ca(2+)-free conditions. Thus, exercise training appears to provoke a decreased expression of G alpha i-2 protein. This, at least in part, results in loss of the inhibitory effect of norepinephrine either on cAMP content or on insulin secretion at the post-calcium events in stimulus-secretion coupling, which, in turn, leads to the blunted inhibitory effects of norepinephrine on insulin secretion.
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MESH Headings
- Adrenergic alpha-Agonists/pharmacology
- Adrenergic alpha-Antagonists/pharmacology
- Animals
- Blood Glucose/metabolism
- Blotting, Western
- Clonidine/pharmacology
- Cyclic AMP/metabolism
- Dose-Response Relationship, Drug
- Down-Regulation
- GTP-Binding Protein alpha Subunit, Gi2
- GTP-Binding Protein alpha Subunits, Gi-Go/genetics
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- In Vitro Techniques
- Insulin/metabolism
- Insulin Secretion
- Islets of Langerhans/metabolism
- Male
- Norepinephrine/pharmacology
- Norepinephrine/physiology
- Physical Conditioning, Animal
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- RNA/analysis
- Rats
- Rats, Wistar
- Receptors, Adrenergic, alpha-2/drug effects
- Receptors, Adrenergic, alpha-2/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Yohimbine/pharmacology
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Affiliation(s)
- Yuriko Urano
- Department of Kinesiology, Graduate School of Sciene, Tokyo Metropolitan University, Tokyo 192-0397, Japan
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6
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Kero JT, Savontaus E, Mikola M, Pesonen U, Koulu M, Keri RA, Nilson JH, Poutanen M, Huhtaniemi IT. Obesity in transgenic female mice with constitutively elevated luteinizing hormone secretion. Am J Physiol Endocrinol Metab 2003; 285:E812-8. [PMID: 12773309 DOI: 10.1152/ajpendo.00367.2002] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Transgenic (TG) female mice, expressing a chimeric bovine luteinizing hormone (LH) beta-subunit/human chorionic gonadotropin beta-subunit COOH-terminal extension (bLHbeta-CTP) gene, produce high levels of circulating LH and serve as a model for functional ovarian hyperandrogenism and follicular cysts. We report here that obesity is a typical feature of these female mice. The mean body weight of the bLHbeta-CTP females was significantly higher than in controls at, and beyond 5 wk of age, and at 5 mo, it was 32% increased. At this age, the amount of white adipose tissue in the bLHbeta-CTP females was significantly increased, as reflected by the weight difference of the retroperitoneal fat pad. In addition, the expression of leptin mRNA in white adipose tissue of the TG females was elevated about twofold. Serum leptin and insulin levels, and food intake, were also increased significantly in the TG females. Brown adipose tissue (BAT) thermogenic activity, as measured by GDP binding to BAT mitochondria, was reduced (P < 0.05). Ovariectomy at the age of 3 wk totally prevented the development of obesity. In summary, the present results show that intact female bLHbeta-CTP mice are obese, have increased food consumption, and reduced BAT thermogenic activity. The weight gain can be explained partly by elevated androgens but is probably also contributed to the increased adrenal steroidogenesis. Hence, the bLHbeta-CTP mice provide a useful model for studying obesity related to elevated LH secretion, with consequent alterations in ovarian and adrenal function.
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Affiliation(s)
- Jukka T Kero
- Department of Physiology, University of Turku, Kiinamyllynkatu 10, 20520 Turku, Finland
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7
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Savontaus E, Rouru J, Malminiemi K, Luukkaa V, Pesonen U, Koulu M, Huupponen R. Effects of chronic celiprolol treatment on brown fat, feeding, and drinking in fa/fa Zucker rats. Pharmacol Biochem Behav 2000; 65:719-24. [PMID: 10764928 DOI: 10.1016/s0091-3057(99)00254-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Celiprolol is a novel beta-adrenoceptor blocking drug that displays clinically favorable effects on glucose and lipid metabolism. Because some other atypical beta-adrenoceptor blocking drugs have been described to act as agonists on beta(3)-adrenoceptors, we aimed to investigate the effects of celiprolol on brown fat and beta(3)-adrenoceptors. Chronic treatment of obese fa/fa Zucker rats with celiprolol (50 mg/kg/day orally for 20 days) increased GDP binding to brown fat mitochondria by 1.5-fold, whereas beta(3)-adrenoceptor agonist ZD7114 ((S)-4-[2-[(2-hydroxy-3-phenoxypropyl)amino]ethoxy]-N-(2-methoxyet hyl )phenoxyacetamide, 3 mg/kg/day) increased the binding by 3.3-fold. Weight gain was reduced by 19% due to decreased water and food intakes in celiprolol-treated rats. Celiprolol did not activate lipolysis in rat adipocytes in vitro or stimulate human beta(3)-adrenoceptors expressed in Chinese hamster ovary cells as measured with Cytosensor microphysiometer. Therefore, celiprolol does not seem to activate brown fat via beta(3)-adrenoceptors.
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Affiliation(s)
- E Savontaus
- Department of Pharmacology and Clinical Pharmacology, University of Turku, Kiinamyllynkatu 10, FIN-20520, Turku, Finland
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8
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Savontaus E, Rouru J, Boss O, Huupponen R, Koulu M. Differential regulation of uncoupling proteins by chronic treatments with beta 3-adrenergic agonist BRL 35135 and metformin in obese fa/fa Zucker rats. Biochem Biophys Res Commun 1998; 246:899-904. [PMID: 9618309 DOI: 10.1006/bbrc.1998.8721] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The expressions of uncoupling proteins 2 and 3 (UCP2; UCP3) mRNA were studied in obese (fa/fa) Zucker rats treated with two weight gain reducing agents for three weeks. The specific beta 3-adrenoceptor agonist BRL 35135 (0.5 mg/kg/day orally) increased the expression of UCP3 mRNA by 3.8-fold (P < 0.0001; two-way ANOVA) and that of UCP1 mRNA by 2.6-fold (P = 0.014) in brown adipose tissue, but had no effect on expression of UCP3 mRNA in white fat or in the soleus muscle, or on UCP2 mRNA expression in brown or white fat. The antihyperglycemic metformin (300 mg/kg/day orally) had no effect on expressions of UCP1, UCP2 or UCP3 in any tissue studied. Concentrations of plasma insulin were significantly correlated with the levels of white fat UCP2 mRNA (in the control group: r = 0.89, P = 0.0015) and UCP3 mRNA (in the control group: r = 0.80, P = 0.009) suggesting that insulin may play a role in the control of UCP2 and UCP3 mRNA expressions in white adipose tissue.
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Affiliation(s)
- E Savontaus
- Department of Pharmacology and Clinical Pharmacology, University of Turku, Finland.
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9
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Savontaus E, Pesonen U, Rouru J, Huupponen R, Koulu M. Effects of ZD7114, a selective beta3-adrenoceptor agonist, on neuroendocrine mechanisms controlling energy balance. Eur J Pharmacol 1998; 347:265-74. [PMID: 9653893 DOI: 10.1016/s0014-2999(98)00120-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Selective beta3-adrenoceptor agonists increase energy expenditure by increasing non-shivering thermogenesis in brown adipose tissue. The aim of this study was to investigate how changes in energy balance affect energy intake and interaction of peripheral metabolic feedback signals with central neuroendocrine mechanisms participating in the control of body energy balance. Expression of preproneuropeptide Y (preproNPY) mRNA in the arcuate nucleus and preprocorticotropin-releasing factor (CRF) mRNA in the paraventricular nucleus were measured by in situ hybridisation technique after 1 day, 1 and 5 weeks of treatment with ZD7114 ((S)-4-[2-[(2-hydroxy-3-phenoxypropyl)amino]ethoxy]-N-(2-methoxyet hyl)phenoxyacetamide, 3 mg kg(-1) day(-1) in drinking water) in obese fa/fa Zucker rats. In addition, expression of leptin mRNA in epididymal fat and serum levels of leptin were analysed. Food intake, body weights, binding of GDP to brown adipose tissue mitochondria, plasma insulin and glucose were also measured. Treatment with ZD7114 significantly reduced weight gain and activated brown adipose tissue thermogenesis, but had no effect on food intake. Expressions of preproNPY or preproCRF mRNAs were similarly not changed by treatment with ZD7114. Furthermore, ZD7114 had no effect on plasma insulin or leptin and the expression of leptin mRNA in epididymal fat. However, statistically significant correlations were found between preproNPY and preproCRF mRNA expressions and brown fat thermogenic activity and plasma insulin levels in the ZD7114 treated rats, but not in the control rats. It is concluded that treatment with ZD7114 markedly activated brown fat thermogenesis, but did not affect neuropeptide Y (NPY) and CRF gene expression per se. However, the correlation analyses suggest that ZD7114 may modulate feedback connections of brown adipose tissue thermogenesis and plasma insulin with the hypothalamic neuroendocrine mechanisms integrating body energy balance.
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Affiliation(s)
- E Savontaus
- Department of Pharmacology and Clinical Pharmacology, University of Turku, Finland.
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10
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Berraondo B, Bonafonte A, Fernandez-Otero MP, Martinez JA. Effects on energy utilization of a beta3-adrenergic agonist in rats fed on a cafeteria diet. Eat Weight Disord 1997; 2:130-7. [PMID: 14655836 DOI: 10.1007/bf03339963] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The antiobesity potential of a new beta3-adrenergic agonist (Trecadrine) was assessed in a cafeteria model of obesity through body composition, thermogenesis and oxygen consumption indicators. Animals fed on a cafeteria diet for 75 days increased body weight and fat content, while muscle mass as a percentage of body weight was reduced in relation to control fed rats. In addition, in vitro brown adipose tissue (BAT) and white adipose tissue (WAT) oxygen consumption was increased in these obese animals as compared with controls. Trecadrine administration reduced weight gain, BAT and WAT stores as well as the respiratory quotient, which was accompanied by an increase in WAT and BAT oxygen consumption and rectal temperature. Moreover, muscle mass as a percentage of body weight maintained the same values as non-obese animals, while an increase in absolute muscle weight was found in Trecadrine-treated obese rats. However, liver weights and in vitro oxygen consumption remained unaltered after cafeteria feeding and Trecadrine administration. Since chronic administration of Trecadrine had no effect on food intake, the stimulation of thermogenesis and oxygen consumption by the beta3-adrenergic agonist in white and brown adipose tissue are apparently responsible for the rise in energy expenditure as well as for the lower weight gain and fat deposition in obese treated rats. Thus, Trecadrine exhibits some promise as a potential treatment for obesity.
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Affiliation(s)
- B Berraondo
- Department of Physiology and Nutrition, University of Navarra, Pamplona, Spain
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11
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Virtanen KA, Rouru J, Hänninen V, Savontaus E, Rouvari T, Teirmaa T, Koulu M, Huupponen R. Chronic treatment with BRL 35135 potentiates the action of insulin on lipid metabolism. Eur J Pharmacol 1997; 332:215-8. [PMID: 9286624 DOI: 10.1016/s0014-2999(97)01104-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The effects of a beta 3-adrenoceptor agonist on insulin-induced changes in lipid metabolism were studied in obese male Zucker (fa/fa) rats during euglycaemic clamp. Rats were treated with BRL 35135 (R*, R*-(+/-)-methyl-4-[2-[2-hydroxy-2-(3-chlorophenyl)-ethyl-amino]-propyl] phenoxyacetate hydrobromide) (0.5 mg/kg per day in drinking water) for three weeks before an euglycaemic hyperinsulinaemic clamp was performed. Insulin infusion lowered serum non-esterified fatty acids and plasma glycerol more efficiently in BRL 35135-treated than in control rats although plasma insulin remained significantly lower in the BRL 35135-treated than in the control rats during the clamp. In conclusion, chronic treatment with BRL 35135 potentiates the effect of insulin on lipid metabolism.
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Affiliation(s)
- K A Virtanen
- Department of Pharmacology and Clinical Pharmacology, University of Turku, Finland.
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12
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Savontaus E, Raasmaja A, Rouru J, Koulu M, Pesonen U, Virtanen R, Savola JM, Huupponen R. Anti-obesity effect of MPV-1743 A III, a novel imidazoline derivative, in genetic obesity. Eur J Pharmacol 1997; 328:207-15. [PMID: 9218703 DOI: 10.1016/s0014-2999(97)83047-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
MPV-1743 A III ((+/-)-4-(5-fluoro-2,3-dihydro-1H-inden-2-yl)-1H-imidazole) is a novel imidazoline derivative. In this study, it was shown to bind with high affinity to alpha2-adrenoceptor subtypes alpha2A (IC50) = 0.66 +/- 0.06 nM), alpha2B (IC50) = 3.8 +/- 0.53 nM), alpha2C (IC50) = 3.1 +/- 0.61 nM) in the recombinant S115 cells and to alpha2D (IC50 = 0.94 +/- 0.10 nM) in the rat submandibular gland. MPV-1743 A III also showed remarkably high affinity to alpha1-adrenoceptors (IC50 = 150 +/- 12 nM) in the rat cerebral cortex and to imidazoline I2b-binding sites (IC50) = 150 +/- 5.0 nM) in the rat liver. The functional alpha2-adrenoceptor antagonistic effect of MPV-1743 A III was demonstrated by studying the ability of orally administered MPV-1743 A III to reverse and prevent the alpha2-adrenoceptor agonist detomidine-induced mydriasis in rat. The anti-obesity effect of MPV-1743 A III was investigated in genetically obese (fa/fa) Zucker rats in two different phases of obesity. Chronic treatment with MPV-1743 A III (0.3 3 mg/kg per day p.o. for 3 weeks) dose dependently decreased weight gain in early-phase obesity. In fully established obesity, GDP binding to mitochondria and expression of uncoupling protein mRNA were increased in brown adipose tissue by MPV-1743 A III indicating an activation of non-shivering thermogenesis. The present study shows that MPV- 1743 A III has a modest anti-obesity effect in the genetic rodent model of obesity. The relative importance of alpha2- and alpha1-adrenoceptors and imidazoline I2b-binding sites in mediating the effects of MPV-1743 A III needs further evaluation.
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MESH Headings
- Adipose Tissue, Brown/metabolism
- Adrenergic alpha-2 Receptor Antagonists
- Adrenergic alpha-Antagonists/pharmacology
- Animals
- Anti-Obesity Agents/pharmacology
- Anti-Obesity Agents/therapeutic use
- Binding Sites
- Cell Line
- Cerebral Cortex/drug effects
- Cerebral Cortex/metabolism
- Eating/drug effects
- Female
- Guanosine Diphosphate/metabolism
- Imidazoles/antagonists & inhibitors
- Imidazoles/pharmacology
- Imidazoles/therapeutic use
- In Vitro Techniques
- Indenes
- Male
- Mydriatics/antagonists & inhibitors
- Mydriatics/pharmacology
- Obesity/drug therapy
- Obesity/genetics
- Obesity/metabolism
- Protein Binding/drug effects
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Rats, Zucker
- Receptors, Adrenergic, alpha-1/drug effects
- Receptors, Adrenergic, alpha-1/metabolism
- Receptors, Adrenergic, alpha-2/drug effects
- Receptors, Adrenergic, alpha-2/metabolism
- Weight Gain/drug effects
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Affiliation(s)
- E Savontaus
- Department of Pharmacology and Clinical Pharmacology, University of Turku, Finland.
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