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Vázquez-Carrillo DI, Ocampo-Ruiz AL, Báez-Meza A, Ramírez- Hernández G, Adán-Castro E, García-Rodrigo JF, Dena-Beltrán JL, de los Ríos EA, Sánchez-Martínez MK, Ortiz MG, Martínez de la Escalera G, Clapp C, Macotela Y. Dopamine D2 receptor antagonist counteracts hyperglycemia and insulin resistance in diet-induced obese male mice. PLoS One 2024; 19:e0301496. [PMID: 38635745 PMCID: PMC11025782 DOI: 10.1371/journal.pone.0301496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 03/18/2024] [Indexed: 04/20/2024] Open
Abstract
Obesity leads to insulin resistance (IR) and type 2 diabetes. In humans, low levels of the hormone prolactin (PRL) correlate with IR, adipose tissue (AT) dysfunction, and increased prevalence of T2D. In obese rats, PRL treatment promotes insulin sensitivity and reduces visceral AT adipocyte hypertrophy. Here, we tested whether elevating PRL levels with the prokinetic and antipsychotic drug sulpiride, an antagonist of dopamine D2 receptors, improves metabolism in high fat diet (HFD)-induced obese male mice. Sulpiride treatment (30 days) reduced hyperglycemia, IR, and the serum and pancreatic levels of triglycerides in obese mice, reduced visceral and subcutaneous AT adipocyte hypertrophy, normalized markers of visceral AT function (PRL receptor, Glut4, insulin receptor and Hif-1α), and increased glycogen stores in skeletal muscle. However, the effects of sulpiride reducing hyperglycemia were also observed in obese prolactin receptor null mice. We conclude that sulpiride reduces obesity-induced hyperglycemia by mechanisms that are independent of prolactin/prolactin receptor activity. These findings support the therapeutic potential of sulpiride against metabolic dysfunction in obesity.
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Affiliation(s)
- Dina I. Vázquez-Carrillo
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
| | - Ana Luisa Ocampo-Ruiz
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
| | - Arelí Báez-Meza
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
| | - Gabriela Ramírez- Hernández
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
| | - Elva Adán-Castro
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
| | - José Fernando García-Rodrigo
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
| | - José Luis Dena-Beltrán
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
| | - Ericka A. de los Ríos
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
| | | | - María Georgina Ortiz
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
| | | | - Carmen Clapp
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
| | - Yazmín Macotela
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
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Ikeda H, Mikami R, Yonemochi N, Waddington JL. Regulation of plasma glucose levels by central dopamine D 2 receptors is impaired in type 1 but not type 2 diabetic mouse models. Eur J Pharmacol 2023; 956:175984. [PMID: 37567458 DOI: 10.1016/j.ejphar.2023.175984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 07/22/2023] [Accepted: 08/09/2023] [Indexed: 08/13/2023]
Abstract
Glucose metabolism is reported to be regulated by the central nervous system, but it is unclear whether this regulation is altered in diabetes. We investigated whether regulation of glucose metabolism by central dopamine D2 receptors is altered in type 1 and type 2 diabetic models. Intracerebroventricular injections of both the dopamine D2 receptor agonist quinpirole and the antagonist l-sulpiride induced hyperglycemia in control mice, but not in streptozotocin (STZ)-induced diabetic mice, a type 1 diabetic model. Hyperglycemia induced by quinpirole or l-sulpiride was diminished following fasting and these drugs did not affect hyperglycemia in the pyruvate tolerance test. In addition, both quinpirole and l-sulpiride increased hepatic glucose-6-phosphatase (G6Pase) mRNA. In STZ-induced diabetic mice, dopamine and dopamine D2 receptor mRNA in the hypothalamus, which regulates glucose homeostasis, were decreased. Hepatic glycogen and G6Pase mRNA were also decreased in STZ-induced diabetic mice. Neither quinpirole nor l-sulpiride increased hepatic G6Pase mRNA in STZ-induced diabetic mice. In diet-induced obesity mice, a type 2 diabetic model, both quinpirole and l-sulpiride induced hyperglycemia, and hypothalamic dopamine and dopamine D2 receptor mRNA were not altered. These results indicate that (i) stimulation or blockade of dopamine D2 receptors causes hyperglycemia by increasing hepatic glycogenolysis, and (ii) stimulation or blockade of dopamine D2 receptors does not affect glucose levels in type 1 but does so in type 2 diabetic models. Moreover, hypothalamic dopaminergic function and hepatic glycogenolysis are decreased in the type 1 diabetic model, which reduces hyperglycemia induced by stimulation or blockade of dopamine D2 receptors.
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Affiliation(s)
- Hiroko Ikeda
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan.
| | - Risa Mikami
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Naomi Yonemochi
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - John L Waddington
- School of Pharmacy and Biomolecular Sciences, RCSI University of Medicine and Health Sciences, 111 St Stephen's Green, Dublin 2, Ireland
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Cincotta AH, Cersosimo E, Alatrach M, Ezrokhi M, Agyin C, Adams J, Chilton R, Triplitt C, Chamarthi B, Cominos N, DeFronzo RA. Bromocriptine-QR Therapy Reduces Sympathetic Tone and Ameliorates a Pro-Oxidative/Pro-Inflammatory Phenotype in Peripheral Blood Mononuclear Cells and Plasma of Type 2 Diabetes Subjects. Int J Mol Sci 2022; 23:ijms23168851. [PMID: 36012132 PMCID: PMC9407769 DOI: 10.3390/ijms23168851] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/01/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022] Open
Abstract
Bromocriptine-QR is a sympatholytic dopamine D2 agonist for the treatment of type 2 diabetes that has demonstrated rapid (within 1 year) substantial reductions in adverse cardiovascular events in this population by as yet incompletely delineated mechanisms. However, a chronic state of elevated sympathetic nervous system activity and central hypodopaminergic function has been demonstrated to potentiate an immune system pro-oxidative/pro-inflammatory condition and this immune phenotype is known to contribute significantly to the advancement of cardiovascular disease (CVD). Therefore, the possibility exists that bromocriptine-QR therapy may reduce adverse cardiovascular events in type 2 diabetes subjects via attenuation of this underlying chronic pro-oxidative/pro-inflammatory state. The present study was undertaken to assess the impact of bromocriptine-QR on a wide range of immune pro-oxidative/pro-inflammatory biochemical pathways and genes known to be operative in the genesis and progression of CVD. Inflammatory peripheral blood mononuclear cell biology is both a significant contributor to cardiovascular disease and also a marker of the body’s systemic pro-inflammatory status. Therefore, this study investigated the effects of 4-month circadian-timed (within 2 h of waking in the morning) bromocriptine-QR therapy (3.2 mg/day) in type 2 diabetes subjects whose glycemia was not optimally controlled on the glucagon-like peptide 1 receptor agonist on (i) gene expression status (via qPCR) of a wide array of mononuclear cell pro-oxidative/pro-inflammatory genes known to participate in the genesis and progression of CVD (OXR1, NRF2, NQO1, SOD1, SOD2, CAT, GSR, GPX1, GPX4, GCH1, HMOX1, BiP, EIF2α, ATF4, PERK, XBP1, ATF6, CHOP, GSK3β, NFkB, TXNIP, PIN1, BECN1, TLR2, TLR4, TLR10, MAPK8, NLRP3, CCR2, GCR, L-selectin, VCAM1, ICAM1) and (ii) humoral measures of sympathetic tone (norepinephrine and normetanephrine), whole-body oxidative stress (nitrotyrosine, TBARS), and pro-inflammatory factors (IL-1β, IL-6, IL-18, MCP-1, prolactin, C-reactive protein [CRP]). Relative to pre-treatment status, 4 months of bromocriptine-QR therapy resulted in significant reductions of mRNA levels in PBMC endoplasmic reticulum stress-unfolded protein response effectors [GRP78/BiP (34%), EIF2α (32%), ATF4 (29%), XBP1 (25%), PIN1 (14%), BECN1 (23%)], oxidative stress response proteins [OXR1 (31%), NRF2 (32%), NQO1 (39%), SOD1 (52%), CAT (26%), GPX1 (33%), GPX4 (31%), GCH1 (30%), HMOX1 (40%)], mRNA levels of TLR pro-inflammatory pathway proteins [TLR2 (46%), TLR4 (20%), GSK3β (19%), NFkB (33%), TXNIP (18%), NLRP3 (32%), CCR2 (24%), GCR (28%)], mRNA levels of pro-inflammatory cellular receptor proteins CCR2 and GCR by 24% and 28%, and adhesion molecule proteins L-selectin (35%) and VCAM1 (24%). Relative to baseline, bromocriptine-QR therapy also significantly reduced plasma levels of norepinephrine and normetanephrine by 33% and 22%, respectively, plasma pro-oxidative markers nitrotyrosine and TBARS by 13% and 10%, respectively, and pro-inflammatory factors IL-18, MCP1, IL-1β, prolactin, and CRP by 21%,13%, 12%, 42%, and 45%, respectively. These findings suggest a unique role for circadian-timed bromocriptine-QR sympatholytic dopamine agonist therapy in reducing systemic low-grade sterile inflammation to thereby reduce cardiovascular disease risk.
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Affiliation(s)
- Anthony H. Cincotta
- VeroScience LLC, Tiverton, RI 02878, USA
- Correspondence: ; Tel.: +1-401-816-0525
| | - Eugenio Cersosimo
- Texas Diabetes Institute, University Health System, San Antonio, TX 78207, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Mariam Alatrach
- Texas Diabetes Institute, University Health System, San Antonio, TX 78207, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | | | - Christina Agyin
- Texas Diabetes Institute, University Health System, San Antonio, TX 78207, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - John Adams
- Texas Diabetes Institute, University Health System, San Antonio, TX 78207, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Robert Chilton
- Texas Diabetes Institute, University Health System, San Antonio, TX 78207, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Curtis Triplitt
- Texas Diabetes Institute, University Health System, San Antonio, TX 78207, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | | | | | - Ralph A. DeFronzo
- Texas Diabetes Institute, University Health System, San Antonio, TX 78207, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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Kabir MT, Ferdous Mitu J, Akter R, Akhtar MF, Saleem A, Al-Harrasi A, Bhatia S, Rahman MS, Damiri F, Berrada M, Rahman MH. Therapeutic potential of dopamine agonists in the treatment of type 2 diabetes mellitus. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:46385-46404. [PMID: 35486279 DOI: 10.1007/s11356-022-20445-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 04/21/2022] [Indexed: 06/14/2023]
Abstract
Diabetes is a global health concern that has affected almost 415 million people globally. Bromocriptine is a dopamine D2 agonist, which is a Food and Drug Administration (FDA)-approved drug to treat type 2 diabetes mellitus (T2DM) patients. However, it is considered that a novel treatment therapy is required which can be used in the treatment of diabetes with or without other antidiabetic agents. Dopamine agonists are usually used in neurological disorders like Parkinson's disease (PD), restless leg syndrome, and hyperprolactinemia. However, dopamine agonists including bromocriptine and cabergoline are also effective in reducing the glycemic level in T2DM patients. Bromocriptine was formerly used for the treatment of PD, hyperprolactinemia, and restless leg syndrome, but now it is used for improving glycemic levels as well as reducing free fatty acids and triglycerides. In addition, cabergoline has been found to be effective in glycemic control, but this drug is yet to be approved by the FDA due to its limitations and lack of study. Findings of the clinical trials of bromocriptine have suggested that it reduces almost 0.4-0.8% glycated hemoglobin and cardiovascular risk by 40% in insulin-resistant patients. Moreover, the safe use of bromocriptine in obese T2DM patients makes it a more attractive option as it causes weight loss. Indeed, bromocriptine is a novel therapy for T2DM patients, as its mechanism of action is unique in T2DM patients with minimal adverse effects. This review summarizes the potential of dopamine agonists in the treatment of T2DM.
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Affiliation(s)
- Md Tanvir Kabir
- Department of Pharmacy, Brac University, 66 Mohakhali, Dhaka, 1212, Bangladesh
| | | | - Raushanara Akter
- Department of Pharmacy, Brac University, 66 Mohakhali, Dhaka, 1212, Bangladesh
| | - Muhammad Furqan Akhtar
- Riphah Institute of Pharmaceutical Sciences, Riphah International University Lahore Campus, Lahore, Pakistan
| | - Ammara Saleem
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Government College University Faisalabad, Faisalabad, Pakistan
| | - Ahmed Al-Harrasi
- Natural & Medical Sciences Research Center, University of Nizwa, 616 Birkat Al Mauz, P.O. Box 33, Nizwa, Oman
| | - Saurabh Bhatia
- Natural & Medical Sciences Research Center, University of Nizwa, 616 Birkat Al Mauz, P.O. Box 33, Nizwa, Oman
- School of Health Science, University of Petroleum and Energy Studies, Prem Nagar, Dehradun, Uttarakhand, 248007, India
| | - Md Sohanur Rahman
- Department of Biochemistry and Molecular Biology, Trust University, Barishal, Ruiya, Nobogram Road, Barishal, 8200, Bangladesh
| | - Fouad Damiri
- Laboratory of Biomolecules and Organic Synthesis (BIOSYNTHO), Department of Chemistry, Faculty of Sciences Ben M'Sick, University Hassan II of Casablanca, Casablanca, Morocco
| | - Mohammed Berrada
- Laboratory of Biomolecules and Organic Synthesis (BIOSYNTHO), Department of Chemistry, Faculty of Sciences Ben M'Sick, University Hassan II of Casablanca, Casablanca, Morocco
| | - Md Habibur Rahman
- Department of Pharmacy, Southeast University, Banani, Dhaka, 1213, Bangladesh.
- Department of Global Medical Science, Wonju College of Medicine, Yonsei University, Wonju, 26426, Gangwon-do, Korea.
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De Iuliis A, Montinaro E, Fatati G, Plebani M, Colosimo C. Diabetes mellitus and Parkinson's disease: dangerous liaisons between insulin and dopamine. Neural Regen Res 2022; 17:523-533. [PMID: 34380882 PMCID: PMC8504381 DOI: 10.4103/1673-5374.320965] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/08/2021] [Accepted: 03/04/2021] [Indexed: 11/13/2022] Open
Abstract
The relationship between diabetes mellitus and Parkinson's disease has been described in several epidemiological studies over the 1960s to date. Molecular studies have shown the possible functional link between insulin and dopamine, as there is strong evidence demonstrating the action of dopamine in pancreatic islets, as well as the insulin effects on feeding and cognition through central nervous system mechanism, largely independent of glucose utilization. Therapies used for the treatment of type 2 diabetes mellitus appear to be promising candidates for symptomatic and/or disease-modifying action in neurodegenerative diseases including Parkinson's disease, while an old dopamine agonist, bromocriptine, has been repositioned for the type 2 diabetes mellitus treatment. This review will aim at reappraising the different studies that have highlighted the dangerous liaisons between diabetes mellitus and Parkinson's disease.
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Affiliation(s)
| | - Ennio Montinaro
- Department of Neurology, Santa Maria University Hospital, Terni, Italy
| | | | - Mario Plebani
- Department of Medicine-DiMED, University of Padova, Italy
- Department of Medicine-DiMED, University of Padova, Padova, Italy; Department of Laboratory Medicine-Hospital of Padova, Padova, Italy
| | - Carlo Colosimo
- Department of Neurology, Santa Maria University Hospital, Terni, Italy
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Wasinski F, Chaves FM, Pedroso JA, Mansano NS, Camporez JP, Gusmão DO, List EO, Kopchick JJ, Frazão R, Szawka RE, Donato J. Growth hormone receptor in dopaminergic neurones regulates stress-induced prolactin release in male mice. J Neuroendocrinol 2021; 33:e12957. [PMID: 33769619 PMCID: PMC9670090 DOI: 10.1111/jne.12957] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 02/03/2021] [Accepted: 02/10/2021] [Indexed: 12/15/2022]
Abstract
Arcuate nucleus (ARH) dopaminergic neurones regulate several biological functions, including prolactin secretion and metabolism. These cells are responsive to growth hormone (GH), although it is still unknown whether GH action on ARH dopaminergic neurones is required to regulate different physiological aspects. Mice carrying specific deletion of GH receptor (GHR) in tyrosine hydroxylase (TH)- or dopamine transporter (DAT)-expressing cells were produced. We investigated possible changes in energy balance, glucose homeostasis, fertility, pup survival and restraint stress-induced prolactin release. GHR deletion in DAT- or TH-expressing cells did not cause changes in food intake, energy expenditure, ambulatory activity, nutrient oxidation, glucose tolerance, insulin sensitivity and counter-regulatory response to hypoglycaemia in male and female mice. In addition, GHR deletion in dopaminergic cells caused no gross effects on reproduction and pup survival. However, restraint stress-induced prolactin release was significantly impaired in DAT- and TH-specific GHR knockout male mice, as well as in pegvisomant-treated wild-type males, whereas an intact response was observed in females. Patch clamp recordings were performed in ARH DAT neurones and, in contrast to prolactin, GH did not cause acute changes in the electrical activity of DAT neurones. Furthermore, TH phosphorylation at Ser40 in ARH neurones and median eminence axonal terminals was not altered in DAT-specific GHR knockout male mice during restraint stress. In conclusion, GH action in dopaminergic neurones is required for stress-induced prolactin release in male mice, suggesting the existence of sex differences in the capacity of GHR signalling to affect prolactin secretion. The mechanism behind this regulation still needs to be identified.
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Affiliation(s)
- Frederick Wasinski
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofísica, Sao Paulo, Brazil
| | - Fernanda M. Chaves
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofísica, Sao Paulo, Brazil
| | - João A.B. Pedroso
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofísica, Sao Paulo, Brazil
| | - Naira S. Mansano
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Anatomia, Sao Paulo, Brazil
| | - João Paulo Camporez
- Universidade de Sao Paulo, Faculdade de Medicina de Ribeirao Preto, Departamento de Fisiologia, Ribeirao Preto, Brazil
| | - Daniela O. Gusmão
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Edward O. List
- Edison Biotechnology Institute and Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
| | - John J. Kopchick
- Edison Biotechnology Institute and Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
| | - Renata Frazão
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Anatomia, Sao Paulo, Brazil
| | - Raphael E. Szawka
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Jose Donato
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofísica, Sao Paulo, Brazil
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Ikeda H, Yonemochi N, Mikami R, Abe M, Kawamura M, Natsume R, Sakimura K, Waddington JL, Kamei J. Central dopamine D 2 receptors regulate plasma glucose levels in mice through autonomic nerves. Sci Rep 2020; 10:22347. [PMID: 33339892 PMCID: PMC7749102 DOI: 10.1038/s41598-020-79292-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 12/07/2020] [Indexed: 02/03/2023] Open
Abstract
Recent evidence suggests that the central nervous system (CNS) regulates plasma glucose levels, but the underlying mechanism is unclear. The present study investigated the role of dopaminergic function in the CNS in regulation of plasma glucose levels in mice. I.c.v. injection of neither the dopamine D1 receptor agonist SKF 38393 nor the antagonist SCH 23390 influenced plasma glucose levels. In contrast, i.c.v. injection of both the dopamine D2 receptor agonist quinpirole and the antagonist l-sulpiride increased plasma glucose levels. Hyperglycemia induced by quinpirole and l-sulpiride was absent in dopamine D2 receptor knockout mice. I.c.v. injection of quinpirole and l-sulpiride each increased mRNA levels of hepatic glucose-6-phosphatase and phosphoenolpyruvate carboxykinase, which are the key enzymes for hepatic gluconeogenesis. Systemic injection of the β2 adrenoceptor antagonist ICI 118,551 inhibited hyperglycemia induced by l-sulpiride, but not by quinpirole. In contrast, hyperglycemia induced by quinpirole, but not by l-sulpiride, was inhibited by hepatic vagotomy. These results suggest that stimulation of central dopamine D2 receptors increases plasma glucose level by increasing hepatic glucose production through parasympathetic nerves, whereas inhibition of central dopamine D2 receptors increases plasma glucose level by increasing hepatic glucose production through sympathetic nerves.
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Affiliation(s)
- Hiroko Ikeda
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan.
| | - Naomi Yonemochi
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Risa Mikami
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Manabu Abe
- Department of Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Meiko Kawamura
- Department of Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Rie Natsume
- Department of Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Kenji Sakimura
- Department of Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - John L Waddington
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Junzo Kamei
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
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The role of spinally located dopamine D 2 receptors in the regulation of the blood glucose level in mice. Pharmacol Rep 2020; 72:1666-1675. [PMID: 32627115 DOI: 10.1007/s43440-020-00126-x] [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: 02/05/2020] [Revised: 06/22/2020] [Accepted: 07/01/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND The possible role of dopamine D2 receptors located in the spinal cord in the regulation of the blood glucose level have not been investigated before. METHODS In the present study, the effect of D2 receptor agonist and antagonist administered intrathecal (it) injection on the blood glucose level were examined in the Institute of Cancer Research (ICR) mice. RESULTS We found that it injection with carmoxirole (D2 receptor agonist) caused an elevation of the blood glucose level in a dose-dependent manner. Carmoxirole-induced increase of the blood glucose was significantly attenuated by L-741,626 (D2 receptor antagonist). Previously, we indicated that intrathecal (it) treatment with 0.1 μg/5 μl pertussis toxin (PTX, a Gi/Go inhibitor) produces a hypoglycemic effect in ICR in a long-term manner. In the present study, it pretreatment with PTX for 6 days almost abolished the hyperglycemic effect induced by carmoxirole. The plasma insulin level was elevated by carmoxirole, and L-741,626 or PTX pretreatment reduced carmoxirole-induced increment of the insulin level. In addition, the plasma corticosterone level was increased by carmoxirole but it pretreatment with L-741,626 or PTX did not affect carmoxirole-induced increment of the corticosterone level. CONCLUSION Our results suggest that D2 receptors located in the spinal cord play an important role in the elevation of the blood glucose level. Spinally located inhibitory G-proteins appear to be involved in hyperglycemic effect induced by carmoxirole.
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Stoelzel CR, Zhang Y, Cincotta AH. Circadian-timed dopamine agonist treatment reverses high-fat diet-induced diabetogenic shift in ventromedial hypothalamic glucose sensing. Endocrinol Diabetes Metab 2020; 3:e00139. [PMID: 32704560 PMCID: PMC7375120 DOI: 10.1002/edm2.139] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 03/28/2020] [Indexed: 12/19/2022] Open
Abstract
INTRODUCTION Within the ventromedial hypothalamus (VMH), glucose inhibitory (GI) neurons sense hypoglycaemia while glucose excitatory (GE) neurons sense hyperglycaemia to initiate counter control mechanisms under normal conditions. However, potential electrophysiological alterations of these two neuronal types in vivo in insulin-resistant states have never been simultaneously fully documented. Further, the anti-diabetic effect of dopamine agonism on this VMH system under insulin resistance has not been studied. METHODS This study examined the impact of a high-fat diet (HFD) on in vivo electrophysiological recordings from VMH GE and GI neurons and the ability of circadian-timed dopamine agonist therapy to reverse any adverse effect of the HFD on such VMH activities and peripheral glucose metabolism. RESULTS HFD significantly inhibited VMH GE neuronal electrophysiological response to local hyperglycaemia (36.3%) and augmented GI neuronal excitation response to local hypoglycaemia (47.0%). Bromocriptine (dopamine agonist) administration at onset of daily activity (but not during the daily sleep phase) completely reversed both VMH GE and GI neuronal aberrations induced by HFD. Such timed treatment also normalized glucose intolerance and insulin resistance. These VMH and peripheral glucose metabolism effects of circadian-timed bromocriptine may involve its known effect to reduce elevated VMH noradrenergic activity in insulin-resistant states as local VMH administration of norepinephrine was observed to significantly inhibit VMH GE neuronal sensing of local hyperglycaemia in insulin-sensitive animals on regular chow diet (52.4%). CONCLUSIONS HFD alters VMH glucose sensing in a manner that potentiates hyperglycaemia and this effect on the VMH can be reversed by appropriately circadian-timed dopamine agonist administration.
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Framnes-DeBoer SN, Bakke E, Yalamanchili S, Peterson H, Sandoval DA, Seeley RJ, Arble DM. Bromocriptine improves glucose tolerance independent of circadian timing, prolactin, or the melanocortin-4 receptor. Am J Physiol Endocrinol Metab 2020; 318:E62-E71. [PMID: 31794265 PMCID: PMC6985791 DOI: 10.1152/ajpendo.00325.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Bromocriptine, a dopamine D2 receptor agonist originally used for the treatment of hyperprolactinemia, is largely successful in reducing hyperglycemia and improving glucose tolerance in type 2 diabetics. However, the mechanism behind bromocriptine's effect on glucose intolerance is unclear. Here, we tested three hypotheses, that bromocriptine may exert its effects on glucose metabolism by 1) decreasing prolactin secretion, 2) indirectly increasing activity of key melanocortin receptors in the central nervous system, or 3) improving/restoring circadian rhythms. Using a diet-induced obese (DIO) mouse model, we established that a 2-wk treatment of bromocriptine is robustly effective at improving glucose tolerance. We then demonstrated that bromocriptine is effective at improving the glucose tolerance of both DIO prolactin-deficient and melanocortin-4 receptor (MC4R)-deficient mice, pointing to bromocriptine's ability to affect glucose tolerance independently of prolactin or MC4R signaling. Finally, we tested bromocriptine's dependence on the circadian system by testing its effectiveness in environmental (e.g., repeated shifts to the light-dark cycle) and genetic (e.g., the Clock mutant mouse) models of circadian disruption. In both models of circadian disruption, bromocriptine was effective at improving glucose tolerance, indicating that a functional or well-aligned endogenous clock is not necessary for bromocriptine's effects on glucose metabolism. Taken together, these results do not support the role of prolactin, MC4R, or the circadian clock as integral to bromocriptine's underlying mechanism. Instead, we find that bromocriptine is a robust diabetic treatment and resilient to genetically induced obesity, diabetes, and circadian disruption.
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Affiliation(s)
| | - Ellen Bakke
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin
| | | | - Hannah Peterson
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin
| | | | - Randy J Seeley
- Department of Surgery, University of Michigan, Ann Arbor, Michigan
| | - Deanna M Arble
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin
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11
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Stice E, Burger K. Neural vulnerability factors for obesity. Clin Psychol Rev 2019; 68:38-53. [PMID: 30587407 PMCID: PMC6397091 DOI: 10.1016/j.cpr.2018.12.002] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 10/05/2018] [Accepted: 12/17/2018] [Indexed: 01/09/2023]
Abstract
Multiple theories identify neural vulnerability factors that may increase risk for overeating and weight gain. Early cross-sectional neuroimaging studies were unable to determine whether aberrant neural responsivity was a risk factor for or a consequence of overeating. More recent obesity risk, prospective, repeated-measures, and experimental neuroimaging studies with humans have advanced knowledge of etiologic processes and neural plasticity resulting from overeating. Herein, we review evidence from these more rigorous human neuroimaging studies, in conjunction with behavioral measures reflecting neural function, as well as experiments with animals that investigated neural vulnerability theories for overeating. Findings provide support for the reward surfeit theory that posits that individuals at risk for obesity initially show hyper-responsivity of reward circuitry to high-calorie food tastes, which theoretically drives elevated intake of such foods. However, findings provide little support for the reward deficit theory that postulates that individuals at risk for obesity show an initial hypo-responsivity of reward circuitry that motives overeating. Further, results provide support for the incentive sensitization and dynamic vulnerability theories that propose that overconsumption of high-calorie foods results in increased reward and attention region responsivity to cues that are associated with hedonic reward from intake of these high-calorie foods via conditioning, as well as a simultaneous decrease in reward region responsivity to high-calorie food tastes. However, there is little evidence that this induced reduction in reward region response to high-calorie food tastes drives an escalation in overeating. Finally, results provide support for the theory that an initial deficit in inhibitory control and a bias for immediate reward contribute to overconsumption of high-calorie foods. Findings imply that interventions that reduce reward and attention region responsivity to food cues and increase inhibitory control should reduce overeating and excessive weight gain, an intervention theory that is receiving support in randomized trials.
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Affiliation(s)
- Eric Stice
- Oregon Research Institute, Eugene, OR, USA.
| | - Kyle Burger
- University of North Carolina, Chapel Hill, NC, USA
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Furigo IC, Suzuki MF, Oliveira JE, Ramos-Lobo AM, Teixeira PDS, Pedroso JA, de Alencar A, Zampieri TT, Buonfiglio DC, Quaresma PGF, Prada PO, Bartolini P, Soares CRJ, Donato J. Suppression of Prolactin Secretion Partially Explains the Antidiabetic Effect of Bromocriptine in ob/ob Mice. Endocrinology 2019; 160:193-204. [PMID: 30462197 DOI: 10.1210/en.2018-00629] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 11/15/2018] [Indexed: 11/19/2022]
Abstract
Previous studies have shown that bromocriptine mesylate (Bromo) lowers blood glucose levels in adults with type 2 diabetes mellitus; however, the mechanism of action of the antidiabetic effects of Bromo is unclear. As a dopamine receptor agonist, Bromo can alter brain dopamine activity affecting glucose control, but it also suppresses prolactin (Prl) secretion, and Prl levels modulate glucose homeostasis. Thus, the objective of the current study was to investigate whether Bromo improves insulin sensitivity via inhibition of Prl secretion. Male and female ob/ob animals (a mouse model of obesity and insulin resistance) were treated with Bromo and/or Prl. Bromo-treated ob/ob mice exhibited lower serum Prl concentration, improved glucose and insulin tolerance, and increased insulin sensitivity in the liver and skeletal muscle compared with vehicle-treated mice. Prl replacement in Bromo-treated mice normalized serum Prl concentration without inducing hyperprolactinemia. Importantly, Prl replacement partially reversed the improvements in glucose homeostasis caused by Bromo treatment. The effects of the Prl receptor antagonist G129R-hPrl on glucose homeostasis were also investigated. We found that central G129R-hPrl infusion increased insulin tolerance of male ob/ob mice. In summary, our findings indicate that part of Bromo effects on glucose homeostasis are associated with decrease in serum Prl levels. Because G129R-hPrl treatment also improved the insulin sensitivity of ob/ob mice, pharmacological compounds that inhibit Prl signaling may represent a promising therapeutic approach to control blood glucose levels in individuals with insulin resistance.
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Affiliation(s)
- Isadora C Furigo
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Miriam F Suzuki
- Biotechnology Center, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, São Paulo, SP, Brazil
| | - João E Oliveira
- Biotechnology Center, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, São Paulo, SP, Brazil
| | - Angela M Ramos-Lobo
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Pryscila D S Teixeira
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - João A Pedroso
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Amanda de Alencar
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Thais T Zampieri
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Daniella C Buonfiglio
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Paula G F Quaresma
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
- Department of Internal Medicine, State University of Campinas, Campinas, São Paulo, SP, Brazil
| | - Patricia O Prada
- School of Applied Sciences, State University of Campinas, Limeira, São Paulo, SP, Brazil
| | - Paolo Bartolini
- Biotechnology Center, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, São Paulo, SP, Brazil
| | - Carlos R J Soares
- Biotechnology Center, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, São Paulo, SP, Brazil
| | - Jose Donato
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
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ter Horst KW, Lammers NM, Trinko R, Opland DM, Figee M, Ackermans MT, Booij J, van den Munckhof P, Schuurman PR, Fliers E, Denys D, DiLeone RJ, la Fleur SE, Serlie MJ. Striatal dopamine regulates systemic glucose metabolism in humans and mice. Sci Transl Med 2018; 10:10/442/eaar3752. [DOI: 10.1126/scitranslmed.aar3752] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 05/03/2018] [Indexed: 12/12/2022]
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Versteeg RI, Koopman KE, Booij J, Ackermans MT, Unmehopa UA, Fliers E, la Fleur SE, Serlie MJ. Serotonin Transporter Binding in the Diencephalon Is Reduced in Insulin-Resistant Obese Humans. Neuroendocrinology 2017; 105:141-149. [PMID: 27626923 PMCID: PMC5637289 DOI: 10.1159/000450549] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 08/02/2016] [Indexed: 11/26/2022]
Abstract
BACKGROUND Altered brain dopaminergic and serotonergic pathways have been shown in obese rodents and humans, but it is unknown whether this is related to obesity per se or to the metabolic derangements associated with obesity. METHODS We performed a case-control study in insulin-sensitive obese (ISO) and insulin-resistant obese (IRO) subjects (n = 12) and age-matched lean controls (n = 8) and measured serotonin transporter (SERT) binding in the whole diencephalon and specifically in the hypothalamus, as well as dopamine transporter (DAT) binding in the striatum using 123I- FP-CIT single-photon emission computed tomography. We assessed insulin sensitivity using the homeostatic model assessment of insulin resistance. RESULTS BMI did not differ between the IRO and ISO subjects. SERT binding in the diencephalon was significantly lower in IRO than in ISO subjects, but was not different between lean and obese subjects. SERT binding in the hypothalamus tended to be reduced in obese versus lean subjects, but was not different between IRO and ISO subjects. Striatal DAT binding was similar between lean and obese subjects as well as between ISO and IRO subjects. CONCLUSIONS We conclude that SERT binding in the diencephalon is reduced in insulin-resistant subjects independently of body weight, while hypothalamic SERT binding tends to be lower in obesity, with no difference between insulin-resistant and insulin-sensitive subjects. This suggests that the metabolic perturbations associated with obesity independently affect SERT binding within the diencephalon.
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Affiliation(s)
| | | | | | - Mariëtte T. Ackermans
- Department of Clinical Chemistry, Laboratory of Endocrinology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | | | | | | | - Mireille J. Serlie
- Department of Endocrinology and Metabolism
- *Mireille J. Serlie, Academic Medical Center, University of Amsterdam, Meibergdreef 9, NL-1105 AZ Amsterdam (The Netherlands), E-Mail
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Chamarthi B, Ezrokhi M, Rutty D, Cincotta AH. Impact of bromocriptine-QR therapy on cardiovascular outcomes in type 2 diabetes mellitus subjects on metformin. Postgrad Med 2016; 128:761-769. [PMID: 27687032 DOI: 10.1080/00325481.2016.1243003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVES Type 2 diabetes mellitus (T2DM) is associated with a substantially increased risk of cardiovascular disease (CVD). Bromocriptine-QR (B-QR), a quick release sympatholytic dopamine D2 receptor agonist, is a FDA-approved therapy for T2DM which may provide CVD risk reduction. Metformin is considered to be an agent with a potential cardioprotective benefit. This large placebo controlled clinical study assessed the impact of B-QR addition to existing metformin therapy on CVD outcomes in T2DM subjects. METHODS 1791 subjects (1208 B-QR; 583 placebo) on metformin ± another anti-diabetes therapy at baseline derived from the Cycloset Safety Trial, a 12-month, randomized, multicenter, placebo-controlled, double-blind study in T2DM, were included in this study. The primary CVD endpoint evaluated was treatment impact on CVD event rate, prespecified as a composite of time to first myocardial infarction, stroke, coronary revascularization, or hospitalization for unstable angina/congestive heart failure. Impact on glycemic control was evaluated as a secondary analysis. RESULTS The composite CVD end point occurred in 16/1208 B-QR treated (1.3%) and 18/583 placebo treated (3.1%) subjects resulting in a 55% CVD hazard risk reduction (intention-to-treat, Cox regression analysis; HR: 0.45 [0.23-0.88], p = 0.028). Kaplan-Meier curves demonstrated a significantly lower cumulative incidence rate of the CVD endpoint in the B-QR treatment group (Log-Rank p = 0.017). In subjects with poor glycemic control (HbA1c ≥ 7.5) at baseline, B-QR therapy relative to placebo resulted in a significant mean %HbA1c reduction of -0.59 at week 12 and -0.51 at week 52 respectively (p < 0.001 for both) and a 10 fold higher percent of subjects achieving HbA1c goal of ≤7% by week 52 (B-QR 30%, placebo 3%; p = 0.003). CONCLUSION These findings suggest that in T2DM subjects on metformin, BQR therapy may represent an effective strategy for reducing CVD risk. Cycloset Safety Trial registration: ClinicalTrials.gov Identifier: NCT00377676.
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Affiliation(s)
- Bindu Chamarthi
- a VeroScience, LLC , Tiverton , RI , USA.,b Division of Endocrinology, Diabetes and Hypertension , Brigham and Women's Hospital , Boston , MA , USA.,c Department of Medicine , Harvard Medical School , Boston , MA , USA
| | | | - Dean Rutty
- d Statistical Operations , Everest Clinical Research Services Inc , Markham , Canada
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Schwartz SS, Zangeneh F. Evidence-based practice use of quick-release bromocriptine across the natural history of type 2 diabetes mellitus. Postgrad Med 2016; 128:828-838. [PMID: 27458683 DOI: 10.1080/00325481.2016.1214059] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVES To provide an evidence-based practice overview on the clinical use of bromocriptine-quick release (QR) across the natural history of type 2 diabetes mellitus (T2DM). METHODS Articles for inclusion were selected after a comprehensive literature search of English-language PubMed articles and identification of other relevant references through other sources. Inclusion criteria were animal studies examining the mechanism of action and efficacy of bromocriptine, and clinical studies examining the safety and efficacy of bromocriptine-QR in patients with T2DM, without a time limitation. RESULTS The brain plays a key role in total body metabolism, in particular ensuring that sufficient levels of glucose are available for proper neural functioning. The hypothalamic suprachiasmatic nucleus (SCN), the body's biological clock, plays a key role in the regulation of seasonal and diurnal variations of insulin sensitivity. A daily surge of dopaminergic activity in the SCN upon waking enables insulin sensitivity throughout the day. When this is disrupted (e.g. by a high fat/sugar diet, stress, altered [diminished] exercise, altered sleep/wake cycle, diabetes), insulin resistance persists throughout the day and overnight. Improving the morning surge in dopaminergic activity with the short-acting dopamine D2 receptor agonist bromocriptine-QR can safely and effectively improve glycemic control, while improving cardiovascular disease risk factors and related adverse events, and reducing sympathetic tone, as demonstrated by 5 reports of the Cycloset Safety Trial and 3 additional clinical studies of bromocriptine-QR. CONCLUSIONS In patients with T2DM, the dopamine D2 receptor agonist bromocriptine-QR has been shown to be well tolerated, efficacious, and a logical treatment option.
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Affiliation(s)
- Stanley S Schwartz
- a Main Line Health System , Wynnewood , PA , USA.,b University of Pennsylvania , Philadelphia , PA , USA
| | - Farhad Zangeneh
- c Endocrine, Diabetes & Osteoporosis Clinic , Sterling , VA , USA
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17
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Dopaminergic drugs in type 2 diabetes and glucose homeostasis. Pharmacol Res 2016; 109:74-80. [DOI: 10.1016/j.phrs.2015.12.029] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 12/22/2015] [Accepted: 12/22/2015] [Indexed: 01/01/2023]
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Song J, Kim J. Degeneration of Dopaminergic Neurons Due to Metabolic Alterations and Parkinson's Disease. Front Aging Neurosci 2016; 8:65. [PMID: 27065205 PMCID: PMC4811934 DOI: 10.3389/fnagi.2016.00065] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 03/17/2016] [Indexed: 12/25/2022] Open
Abstract
The rates of metabolic diseases, such as type 2 diabetes mellitus (T2DM), obesity, and cardiovascular disease (CVD), markedly increase with age. In recent years, studies have reported an association between metabolic changes and various pathophysiological mechanisms in the central nervous system (CNS) in patients with metabolic diseases. Oxidative stress and hyperglycemia in metabolic diseases lead to adverse neurophysiological phenomena, including neuronal loss, synaptic dysfunction, and improper insulin signaling, resulting in Parkinson’s disease (PD). In addition, several lines of evidence suggest that alterations of CNS environments by metabolic changes influence the dopamine neuronal loss, eventually affecting the pathogenesis of PD. Thus, we reviewed recent findings relating to degeneration of dopaminergic neurons during metabolic diseases. We highlight the fact that using a metabolic approach to manipulate degeneration of dopaminergic neurons can serve as a therapeutic strategy to attenuate pathology of PD.
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Affiliation(s)
- Juhyun Song
- Department of Biomedical Engineering, Dongguk University Seoul, South Korea
| | - Jongpil Kim
- Department of Biomedical Engineering, Dongguk University Seoul, South Korea
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Raskin P, Cincotta AH. Bromocriptine-QR therapy for the management of type 2 diabetes mellitus: developmental basis and therapeutic profile summary. Expert Rev Endocrinol Metab 2016; 11:113-148. [PMID: 30058874 DOI: 10.1586/17446651.2016.1131119] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
An extended series of studies indicate that endogenous phase shifts in circadian neuronal input signaling to the biological clock system centered within the hypothalamic suprachiasmatic nucleus (SCN) facilitates shifts in metabolic status. In particular, a diminution of the circadian peak in dopaminergic input to the peri-SCN facilitates the onset of fattening, insulin resistance and glucose intolerance while reversal of low circadian peak dopaminergic activity to the peri-SCN via direct timed dopamine administration to this area normalizes the obese, insulin resistant, glucose intolerant state in high fat fed animals. Systemic circadian-timed daily administration of a potent dopamine D2 receptor agonist, bromocriptine, to increase diminished circadian peak dopaminergic hypothalamic activity across a wide variety of animal models of metabolic syndrome and type 2 diabetes mellitus (T2DM) results in improvements in the obese, insulin resistant, glucose intolerant condition by improving hypothalamic fuel sensing and reducing insulin resistance, elevated sympathetic tone, and leptin resistance. A circadian-timed (within 2 hours of waking in the morning) once daily administration of a quick release formulation of bromocriptine (bromocriptine-QR) has been approved for the treatment of T2DM by the U.S. Food and Drug Administration. Clinical studies with such bromocriptine-QR therapy (1.6 to 4.8 mg/day) indicate that it improves glycemic control by reducing postprandial glucose levels without raising plasma insulin. Across studies of various T2DM populations, bromocriptine-QR has been demonstrated to reduce HbA1c by -0.5 to -1.7. The drug has a good safety profile with transient mild to moderate nausea, headache and dizziness as the most frequent adverse events noted with the medication. In a large randomized clinical study of T2DM subjects, bromocriptine-QR exposure was associated with a 42% hazard ratio reduction of a pre-specified adverse cardiovascular endpoint including myocardial infarction, stroke, hospitalization for congestive heart failure, revascularization surgery, or unstable angina. Bromocriptine-QR represents a novel method of treating T2DM that may have benefits for cardiovascular disease as well.
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Affiliation(s)
- Philip Raskin
- a Southwestern Medical Center , University of Texas , Dallas , TX , USA
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Abstract
Prolactin (PRL) has been long deemed as a hormone involved only in female reproduction. However, PRL is a surprising hormone and, since its identification in the 1970s, its attributed functions have greatly increased. However, its specific role in male health is still widely unknown. Recently, low PRL has been associated with reduced ejaculate and seminal vesicle volume in infertile subjects. In addition, in men consulting for sexual dysfunction, hypoprolactinemia has been associated with erectile dysfunction and premature ejaculation, findings further confirmed in the general European population and infertile men. Several metabolic derangements, recapitulating metabolic syndrome, have also been associated with low PRL both in men with sexual dysfunction and from the general European population. In men with sexual dysfunction, followed-up for more than 4 years, low PRL was identified as an independent predictor of the incidence of major adverse cardiovascular events. Finally, an association with anxiety or depressive symptoms has been found in men with sexual dysfunction and from the general European population. While a direct role for impaired PRL function in the pathogenesis of these reproductive, sexual, metabolic and psychological disorders is conceivable, the possibility that low PRL is a mirror of an increased dopaminergic or a decreased serotonergic tone cannot be ruled-out. Hyperactivity of the dopaminergic system can explain only a few of the aforementioned findings, whereas a hypo-serotonergic tone fits well with the clinical features associated with low PRL, and there is significant evidence supporting the hypothesis that PRL could be a mirror of serotonin in the brain.
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Affiliation(s)
- Giulia Rastrelli
- Sexual Medicine and Andrology Unit, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Pieraccini, 6, 50139, Florence, Italy
| | - Giovanni Corona
- Sexual Medicine and Andrology Unit, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Pieraccini, 6, 50139, Florence, Italy
- Endocrinology Section, Maggiore Hospital, Largo Nigrisoli 2, 40133, Bologna, Italy
| | - Mario Maggi
- Sexual Medicine and Andrology Unit, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Pieraccini, 6, 50139, Florence, Italy.
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Bell DSH. Focusing on Cardiovascular Disease in Type 2 Diabetes Mellitus: An Introduction to Bromocriptine QR. Postgrad Med 2015; 124:121-35. [DOI: 10.3810/pgm.2012.09.2598] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Roe ED, Chamarthi B, Raskin P. Impact of Bromocriptine-QR Therapy on Glycemic Control and Daily Insulin Requirement in Type 2 Diabetes Mellitus Subjects Whose Dysglycemia Is Poorly Controlled on High-Dose Insulin: A Pilot Study. J Diabetes Res 2015; 2015:834903. [PMID: 26060825 PMCID: PMC4427808 DOI: 10.1155/2015/834903] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/28/2015] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The concurrent use of a postprandial insulin sensitizing agent, such as bromocriptine-QR, a quick release formulation of bromocriptine, a dopamine D2 receptor agonist, may offer a strategy to improve glycemic control and limit/reduce insulin requirement in type 2 diabetes (T2DM) patients on high-dose insulin. This open label pilot study evaluated this potential utility of bromocriptine-QR. METHODS Ten T2DM subjects on metformin (1-2 gm/day) and high-dose (TDID ≥ 65 U/day) basal-bolus insulin were enrolled to receive once daily (morning) bromocriptine-QR (1.6-4.8 mg/day) for 24 weeks. Subjects with at least one postbaseline HbA1c measurement (N = 8) were analyzed for change from baseline HbA(1c), TDID, and postprandial glucose area under the curve of a four-hour mixed meal tolerance test (MMTT). RESULTS Compared to the baseline, average HbA1c decreased 1.76% (9.74 ± 0.56 to 7.98 ± 0.36, P = 0.01), average TDID decreased 27% (199 ± 33 to 147 ± 31, P = 0.009), and MMTT AUC(60-240) decreased 32% (P = 0.04) over the treatment period. The decline in HbA(1c) and TDID was observed at 8 weeks and sustained over the remaining 16-week study duration. CONCLUSION In this study, bromocriptine-QR therapy improved glycemic control and meal tolerance while reducing insulin requirement in T2DM subjects poorly controlled on high-dose insulin therapy.
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Affiliation(s)
- Erin D. Roe
- University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Bindu Chamarthi
- Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
- *Bindu Chamarthi:
| | - Philip Raskin
- University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
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Chamarthi B, Gaziano JM, Blonde L, Vinik A, Scranton RE, Ezrokhi M, Rutty D, Cincotta AH. Timed Bromocriptine-QR Therapy Reduces Progression of Cardiovascular Disease and Dysglycemia in Subjects with Well-Controlled Type 2 Diabetes Mellitus. J Diabetes Res 2015; 2015:157698. [PMID: 26060823 PMCID: PMC4427775 DOI: 10.1155/2015/157698] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/02/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Type 2 diabetes (T2DM) patients, including those in good glycemic control, have an increased risk of cardiovascular disease (CVD). Maintaining good glycemic control may reduce long-term CVD risk. However, other risk factors such as elevated vascular sympathetic tone and/or endothelial dysfunction may be stronger potentiators of CVD. This study evaluated the impact of bromocriptine-QR, a sympatholytic dopamine D2 receptor agonist, on progression of metabolic disease and CVD in T2DM subjects in good glycemic control (HbA1c ≤ 7.0%). METHODS 1834 subjects (1219 bromocriptine-QR; 615 placebo) with baseline HbA1c ≤ 7.0% derived from the Cycloset Safety Trial (this trial is registered with ClinicalTrials.gov Identifier: NCT00377676), a 12-month, randomized, multicenter, placebo-controlled, double-blind study in T2DM, were evaluated. Treatment impact upon a prespecified composite CVD endpoint (first myocardial infarction, stroke, coronary revascularization, or hospitalization for angina/congestive heart failure) and the odds of losing glycemic control (HbA1c >7.0% after 52 weeks of therapy) were determined. RESULTS Bromocriptine-QR reduced the CVD endpoint by 48% (intention-to-treat; HR: 0.52 [0.28-0.98]) and 52% (on-treatment analysis; HR: 0.48 [0.24-0.95]). Bromocriptine-QR also reduced the odds of both losing glycemic control (OR: 0.63 (0.47-0.85), p = 0.002) and requiring treatment intensification to maintain HbA1c ≤ 7.0% (OR: 0.46 (0.31-0.69), p = 0.0002). CONCLUSIONS Bromocriptine-QR therapy slowed the progression of CVD and metabolic disease in T2DM subjects in good glycemic control.
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Affiliation(s)
- Bindu Chamarthi
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women's Hospital, 221 Longwood Avenue, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- VeroScience LLC, 1334 Main Road, Tiverton, RI 02878, USA
- *Bindu Chamarthi:
| | - J. Michael Gaziano
- Harvard Medical School, Boston, MA, USA
- Veterans Affairs Healthcare System, 1400 VFW Parkway, W Roxbury, Boston, MA 02132, USA
- Divisions of Aging, Cardiology and Preventive Medicine, Brigham and Women's Hospital, 75 Francis Street, Boston, MA, USA
| | - Lawrence Blonde
- Ochsner Medical Center, 1514 Jefferson Hwy, New Orleans, LA 70121, USA
| | - Aaron Vinik
- Eastern Virginia Medical School Strelitz Diabetes Center and Neuroendocrine Unit, 855 W. Brambleton Avenue, Norfolk, VA 23510, USA
| | | | | | - Dean Rutty
- Everest Clinical Research Services Inc., 675 Cochrane Dr., Markham, ON, Canada L3R 0B8
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la Fleur SE, Serlie MJ. The interaction between nutrition and the brain and its consequences for body weight gain and metabolism; studies in rodents and men. Best Pract Res Clin Endocrinol Metab 2014; 28:649-59. [PMID: 25256761 DOI: 10.1016/j.beem.2014.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Aberrant feeding behavior can lead to obesity and obesity-related medical consequences, such as insulin resistance and diabetes. Although alterations in glucose metabolism (i.e. insulin resistance), in the presence of excessive fat tissue are often explained by the consequences of dysfunctional adipose tissue, evidence is emerging that also altered brain functions might be an important determinant of insulin resistance. In this review, we provide an overview of how feeding behavior and obesity interact with brain circuitry and how these interactions affect glucose metabolism. Because brain circuitries involved in food intake have been shown to partly control glucose metabolism as well, targeting these circuitries in obese subjects might not only affect food intake and body weight but also glucose metabolism.
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Affiliation(s)
- Susanne E la Fleur
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Meibergdreeg 9, F2-154, 1105 AZ Amsterdam, The Netherlands.
| | - Mireille J Serlie
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Meibergdreeg 9, F2-154, 1105 AZ Amsterdam, The Netherlands
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Guigas B, de Leeuw van Weenen JE, van Leeuwen N, Simonis-Bik AM, van Haeften TW, Nijpels G, Houwing-Duistermaat JJ, Beekman M, Deelen J, Havekes LM, Penninx BWJH, Vogelzangs N, van 't Riet E, Dehghan A, Hofman A, Witteman JC, Uitterlinden AG, Grarup N, Jørgensen T, Witte DR, Lauritzen T, Hansen T, Pedersen O, Hottenga J, Romijn JA, Diamant M, Kramer MHH, Heine RJ, Willemsen G, Dekker JM, Eekhoff EM, Pijl H, de Geus EJ, Slagboom PE, 't Hart LM. Sex-specific effects of naturally occurring variants in the dopamine receptor D2 locus on insulin secretion and type 2 diabetes susceptibility. Diabet Med 2014; 31:1001-8. [PMID: 24724616 DOI: 10.1111/dme.12464] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 01/13/2014] [Accepted: 04/08/2014] [Indexed: 12/21/2022]
Abstract
AIMS Modulation of dopamine receptor D2 (DRD2) activity affects insulin secretion in both rodents and isolated pancreatic β-cells. We hypothesized that single nucleotide polymorphisms in the DRD2/ANKK1 locus may affect susceptibility to type 2 diabetes in humans. METHODS Four potentially functional variants in the coding region of the DRD2/ANKK1 locus (rs1079597, rs6275, rs6277, rs1800497) were genotyped and analysed for type 2 diabetes susceptibility in up to 25 000 people (8148 with type 2 diabetes and 17687 control subjects) from two large independent Dutch cohorts and one Danish cohort. In addition, 340 Dutch subjects underwent a 2-h hyperglycaemic clamp to investigate insulin secretion. Since sexual dimorphic associations related to DRD2 polymorphisms have been previously reported, we also performed a gender-stratified analysis. RESULTS rs1800497 at the DRD2/ANKK1 locus was associated with a significantly increased risk for type 2 diabetes in women (odds ratio 1.14 (1.06-1.23); P = 4.1*10⁴) but not in men (odds ratio 1.00 (95% CI 0.93-1.07); P = 0.92) or the combined group. Although rs1800497 was not associated with insulin secretion, we did find another single nucleotide polymorphism in this locus, rs6275, to be associated with increased first-phase glucose-stimulated insulin secretion in women (P = 5.5*10⁴) but again not in men (P = 0.34). CONCLUSION The present data identify DRD2/ANKK1 as a potential sex-specific type 2 diabetes susceptibility gene.
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Affiliation(s)
- B Guigas
- Department of Molecular Cell Biology, Leiden University Medical Centre, Leiden, The Netherlands; Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
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Deas E, Piipari K, Machhada A, Li A, Gutierrez-del-Arroyo A, Withers DJ, Wood NW, Abramov AY. PINK1 deficiency in β-cells increases basal insulin secretion and improves glucose tolerance in mice. Open Biol 2014; 4:140051. [PMID: 24806840 PMCID: PMC4042854 DOI: 10.1098/rsob.140051] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The Parkinson's disease (PD) gene, PARK6, encodes the PTEN-induced putative kinase 1 (PINK1) mitochondrial kinase, which provides protection against oxidative stress-induced apoptosis. Given the link between glucose metabolism, mitochondrial function and insulin secretion in β-cells, and the reported association of PD with type 2 diabetes, we investigated the response of PINK1-deficient β-cells to glucose stimuli to determine whether loss of PINK1 affected their function. We find that loss of PINK1 significantly impairs the ability of mouse pancreatic β-cells (MIN6 cells) and primary intact islets to take up glucose. This was accompanied by higher basal levels of intracellular calcium leading to increased basal levels of insulin secretion under low glucose conditions. Finally, we investigated the effect of PINK1 deficiency in vivo and find that PINK1 knockout mice have improved glucose tolerance. For the first time, these combined results demonstrate that loss of PINK1 function appears to disrupt glucose-sensing leading to enhanced insulin release, which is uncoupled from glucose uptake, and suggest a key role for PINK1 in β-cell function.
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Affiliation(s)
- Emma Deas
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
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Lammers NM, Sondermeijer BM, Twickler TB(M, de Bie RM, Ackermans MT, Fliers E, Schuurman PR, La Fleur SE, Serlie MJ. Subthalamic nucleus stimulation does not influence basal glucose metabolism or insulin sensitivity in patients with Parkinson's disease. Front Neurosci 2014; 8:95. [PMID: 24860415 PMCID: PMC4018563 DOI: 10.3389/fnins.2014.00095] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 04/13/2014] [Indexed: 11/21/2022] Open
Abstract
Animal studies have shown that central dopamine signaling influences glucose metabolism. As a first step to show this association in an experimental setting in humans, we studied whether deep brain stimulation (DBS) of the subthalamic nucleus (STN), which modulates the basal ganglia circuitry, alters basal endogenous glucose production (EGP) or insulin sensitivity in patients with Parkinson's disease (PD). We studied 8 patients with PD treated with DBS STN, in the basal state and during a hyperinsulinemic euglycemic clamp using a stable glucose isotope, in the stimulated and non-stimulated condition. We measured EGP, hepatic insulin sensitivity, peripheral insulin sensitivity (Rd), resting energy expenditure (REE), glucoregulatory hormones, and Parkinson symptoms, using the Unified Parkinson's Disease Rating Scale (UPDRS). Basal plasma glucose and EGP did not differ between the stimulated and non-stimulated condition. Hepatic insulin sensitivity was similar in both conditions and there were no significant differences in Rd and plasma glucoregulatory hormones between DBS on and DBS off. UPDRS was significantly higher in the non-stimulated condition. DBS of the STN in patients with PD does not influence basal EGP or insulin sensitivity. These results suggest that acute modulation of the motor basal ganglia circuitry does not affect glucose metabolism in humans.
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Affiliation(s)
- Nicolette M. Lammers
- Department of Endocrinology and Metabolism, Academic Medical CenterAmsterdam, Netherlands
| | | | - Th. B. (Marcel) Twickler
- Department of Diabetology, Endocrinology and Metabolic Diseases, Antwerp University HospitalAntwerp, Belgium
| | - Rob M. de Bie
- Department of Neurology, Academic Medical CenterAmsterdam, Netherlands
| | - Mariëtte T. Ackermans
- Laboratory of Endocrinology, Department of Clinical Chemistry, Academic Medical CenterAmsterdam, Netherlands
| | - Eric Fliers
- Department of Endocrinology and Metabolism, Academic Medical CenterAmsterdam, Netherlands
| | | | - Susanne E. La Fleur
- Laboratory of Endocrinology, Department of Clinical Chemistry, Academic Medical CenterAmsterdam, Netherlands
| | - Mireille J. Serlie
- Department of Endocrinology and Metabolism, Academic Medical CenterAmsterdam, Netherlands
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Portero McLellan KC, Wyne K, Villagomez ET, Hsueh WA. Therapeutic interventions to reduce the risk of progression from prediabetes to type 2 diabetes mellitus. Ther Clin Risk Manag 2014; 10:173-88. [PMID: 24672242 PMCID: PMC3964168 DOI: 10.2147/tcrm.s39564] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Clinical trials have demonstrated that it is possible to prevent diabetes through lifestyle modification, pharmacological intervention, and surgery. This review aims to summarize the effectiveness of these various therapeutic interventions in reducing the risk of progression of prediabetes to diabetes, and address the challenges to implement a diabetes prevention program at a community level. Strategies focusing on intensive lifestyle changes are not only efficient but cost-effective and/or cost-saving. Indeed, lifestyle intervention in people at high risk for type 2 diabetes mellitus (T2DM) has been successful in achieving sustained behavioral changes and a reduction in diabetes incidence even after the counseling is stopped. Although prediabetes is associated with health and economic burdens, it has not been adequately addressed by interventions or regulatory agencies in terms of prevention or disease management. Lifestyle intervention strategies to prevent T2DM should be distinct for different populations around the globe and should emphasize sex, age, ethnicity, and cultural and geographical considerations to be feasible and to promote better compliance. The translation of diabetes prevention research at a population level, especially finding the most effective methods of preventing T2DM in various societies and cultural settings remains challenging, but must be accomplished to stop this worldwide epidemic.
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Affiliation(s)
| | - Kathleen Wyne
- Division of Diabetes, Obesity and Lipids, Department of Medicine, The Methodist Hospital Diabetes and Metabolism Institute, and the Houston Methodist Research Institute, Weill Cornell Medical College, Houston, TX, USA
| | - Evangelina Trejo Villagomez
- Division of Diabetes, Obesity and Lipids, Department of Medicine, The Methodist Hospital Diabetes and Metabolism Institute, and the Houston Methodist Research Institute, Weill Cornell Medical College, Houston, TX, USA
| | - Willa A Hsueh
- Division of Diabetes, Obesity and Lipids, Department of Medicine, The Methodist Hospital Diabetes and Metabolism Institute, and the Houston Methodist Research Institute, Weill Cornell Medical College, Houston, TX, USA
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Ezrokhi M, Luo S, Trubitsyna Y, Cincotta AH. Neuroendocrine and metabolic components of dopamine agonist amelioration of metabolic syndrome in SHR rats. Diabetol Metab Syndr 2014; 6:104. [PMID: 25937836 PMCID: PMC4416398 DOI: 10.1186/1758-5996-6-104] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 09/16/2014] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND The hypertensive, pro-inflammatory, obese state is strongly coupled to peripheral and hepatic insulin resistance (in composite termed metabolic syndrome [MS]). Hepatic pro-inflammatory pathways have been demonstrated to initiate or exacerbate hepatic insulin resistance and contribute to fatty liver, a correlate of MS. Previous studies in seasonally obese animals have implicated an important role for circadian phase-dependent increases in hypothalamic dopaminergic tone in the maintenance of the lean, insulin sensitive condition. However, mechanisms driving this dopaminergic effect have not been fully delineated and the impact of such dopaminergic function upon the above mentioned parameters of MS, particularly upon key intra-hepatic regulators of liver inflammation and lipid and glucose metabolism have never been investigated. OBJECTIVE This study therefore investigated the effects of timed daily administration of bromocriptine, a potent dopamine D2 receptor agonist, on a) ventromedial hypothalamic catecholamine activity, b) MS and c) hepatic protein levels of key regulators of liver inflammation and glucose and lipid metabolism in a non-seasonal model of MS - the hypertensive, obese SHR rat. METHODS Sixteen week old SHR rats maintained on 14 hour daily photoperiods were treated daily for 16 days with bromocriptine (10 mg/kg, i.p.) or vehicle at 1 hour before light offset and, subsequent to blood pressure recordings on day 14, were then utilized for in vivo microdialysis of ventromedial hypothalamic catecholamine activity or sacrificed for the analyses of MS factors and regulators of hepatic metabolism. Normal Wistar rats served as wild-type controls for hypothalamic activity, body fat levels, and insulin sensitivity. RESULTS Bromocriptine treatment significantly reduced ventromedial hypothalamic norepinephrine and serotonin levels to the normal range and systolic and diastolic blood pressures, retroperitoneal body fat level, plasma insulin and glucose levels and HOMA-IR relative to vehicle treated SHR controls. Such treatment also reduced plasma levels of C-reactive protein, leptin, and norepinephrine and increased that of plasma adiponectin significantly relative to SHR controls. Finally, bromocriptine treatment significantly reduced hepatic levels of several pro-inflammatory pathway proteins and of the master transcriptional activators of lipogenesis, gluconeogenesis, and free fatty acid oxidation versus control SHR rats. CONCLUSION These findings indicate that in SHR rats, timed daily dopamine agonist treatment improves hypothalamic and neuroendocrine pathologies associated with MS and such neuroendocrine events are coupled to a transformation of liver metabolism potentiating a reduction of elevated lipogenic and gluconeogenic capacity. This liver effect may be driven in part by concurrent reductions in hyperinsulinemia and sympathetic tone as well as by reductions in intra-hepatic inflammation.
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Ikegami M, Ikeda H, Ohashi T, Ohsawa M, Ishikawa Y, Kai M, Kamei A, Kamei J. Olanzapine increases hepatic glucose production through the activation of hypothalamic adenosine 5'-monophosphate-activated protein kinase. Diabetes Obes Metab 2013; 15:1128-35. [PMID: 23782571 DOI: 10.1111/dom.12148] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Revised: 02/22/2013] [Accepted: 06/11/2013] [Indexed: 11/30/2022]
Abstract
AIMS To investigate the mechanism of the metabolic disturbance induced by the atypical antipsychotic olanzapine, we examined whether adenosine 5'-monophosphate-activated protein kinase (AMPK) in the hypothalamus and hepatic glucose production are involved in the effect of olanzapine. METHODS Male 6-week-old ICR mice were used. Blood glucose levels were determined by the glucose oxidase method. The mRNA levels of gluconeogenic or glycolytic enzymes were measured by reverse transcription polymerase chain reaction (RT-PCR). AMPK expression was measured by Western blotting. RESULTS Systemic injection of olanzapine increased blood glucose levels in both unfasted and fasted mice. However, the increase in fasted mice was less than that in unfasted mice. Central administration of olanzapine also increased the blood glucose levels in unfasted mice, but not in fasted mice. In a pyruvate tolerance test, olanzapine significantly increased blood glucose levels. In addition, olanzapine increased the mRNA levels of glucose-6-phosphatase (G6Pase), a gluconeogenic enzyme, in the liver. Furthermore, olanzapine increased phosphorylated AMPK in the hypothalamus of unfasted mice, and olanzapine-induced hyperglycaemia was inhibited by the AMPK inhibitor compound C. Central administration of the AMPK activator AICAR significantly increased G6Pase mRNA levels in the liver and blood glucose levels. Moreover, both olanzapine- and AICAR-induced hyperglycaemia were attenuated by the β-adrenergic receptor antagonist propranolol, suggesting that olanzapine and AICAR induce hepatic glucose production through the sympathetic nervous system. CONCLUSIONS Our results indicate that olanzapine activates AMPK in the hypothalamus, which increases hepatic glucose production via the sympathetic nervous system.
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Affiliation(s)
- M Ikegami
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan
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Vinik AI, Cincotta AH, Scranton RE, Bohannon N, Ezrokhi M, Gaziano JM. Effect of bromocriptine-QR on glycemic control in subjects with uncontrolled hyperglycemia on one or two oral anti-diabetes agents. Endocr Pract 2013. [PMID: 23186965 DOI: 10.4158/ep12187.or] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE To investigate the effect of Bromocriptine-QR on glycemic control in patients with type 2 diabetes whose glycemia is poorly controlled on one or two oral anti-diabetes agents. METHODS Five hundred fifteen Type 2 Diabetes Mellitus (T2DM) subjects (ages 18 to 80 and average body mass index [BMI] of 32.7) with baseline HbA1c ≥ 7.5 and on one or two oral anti-diabetes (OAD) medications (metformin, sulfonylurea, and/or thiazolidinediones) were randomized 2:1 to bromocriptine-QR (1.6 to 4.8 mg/day) or placebo for a 24 week treatment period. Study investigators were allowed to adjust, if necessary, subject anti-diabetes medications during the study to attempt to achieve glycemic control in case of glycemic deterioration. The impact of bromocriptine-QR treatment intervention on glycemic control was assessed in subjects on any one or two OADs (ALL treatment category) (N = 515), or on metformin with or without another OAD (Met/OAD treatment category) (N = 356), or on metformin plus a sulfonylurea (Met/SU treatment category) (N = 245) 1) by examining the between group difference in change from baseline a) concomitant OAD medication changes during the study, and b) HbA1c and 2) by determining the odds of reaching HbA1c of ≤ 7.0% on bromocriptine-QR versus placebo. RESULTS Significantly more patients (approximately 1.5 to 2-fold more; P<.05) intensified concomitant anti-diabetes medication therapy during the study in the placebo versus the bromocriptine-QR arm. In subjects that did not change the intensity of the baseline diabetes therapy (72%), and that were on any one or two OADs (ALL), or on metformin with or without another OAD (Met/OAD), or on metformin plus sulfonylurea (Met/SU), the HbA1c change for bromocriptine-QR versus placebo was -0.47 versus +0.22 (between group delta of -0.69, P<.0001), -0.55 versus +0.26 (between group delta of -0.81, P<.0001) and -0.63 versus +0.20 (between group delta of -0.83, P<.0001) respectively, after 24 weeks on therapy. The odds ratio of reaching HbA1c of ≤ 7.0% was 6.50, 12.03 and 11.45 (P<.0002) for these three groups, respectively. CONCLUSION In T2DM subjects whose hyperglycemia is poorly controlled on one or two oral agents, bromocriptine-QR therapy for 24 weeks can provide significant added improvement in glycemic control relative to adding placebo.
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Affiliation(s)
- Aaron I Vinik
- Strelitz Diabetes Center and Neuroendocrine Unit, Norfolk, Virginia, USA
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Brunerova L, Potockova J, Horacek J, Suchy J, Andel M. Central dopaminergic activity influences metabolic parameters in healthy men. Neuroendocrinology 2013; 97:132-8. [PMID: 22947694 DOI: 10.1159/000338405] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 03/18/2012] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS Central dopaminergic activity is probably linked to regulation of glucose and lipid metabolism and weight maintenance. The aim of our study was to evaluate the relationship between central dopaminergic activity measured using the apomorphine challenge test and metabolic parameters in healthy men. METHODS Forty-two healthy men (average age 43.5 ± 7.4 years, body mass index, BMI, 27.4 ± 5.7) were examined anthropometrically and biochemically (glycemia, lipids, glycated hemoglobin). Central dopaminergic activity was assessed as the area under the curve (AUC) of prolactin (PRL) and growth hormone (GH) responses to the apomorphine challenge test after sublingual administration of apomorphine in a dose of 0.033 mg/kg. Insulin resistance was quantified by calculation of glucose disposal and metabolic clearance rate during a euglycemic hyperinsulinemic clamp on two insulin levels (1 and 10 mIU/kg/min). Linear regression was used for statistical analysis. RESULTS Hormonal responses correlated negatively with age (for AUC/GH r = -0.33; p = 0.031) and BMI (AUC/GH r = -0.41; p = 0.007). After adjustment for age and BMI, a statistically significant negative correlations between AUC/PRL and total cholesterol (r = -0.41; p = 0.007), AUC/GH and HbA1c (r = -0.37; p = 0.016) and AUC/GH and HOMA (homeostasis model assessment; r = -0.345; p = 0.025) were observed. CONCLUSION Central dopaminergic activity declines with age and BMI. Higher total cholesterol, glycated hemoglobin and insulin resistance parameters are connected with lower central dopamine tone.
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Affiliation(s)
- Ludmila Brunerova
- Diabetologic Center, Second Department of Internal Medicine, Faculty Hospital Kralovske Vinohrady and Third Faculty of Medicine, Charles University, Prague, Czech Republic.
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Ikegami M, Ikeda H, Ohashi T, Kai M, Osada M, Kamei A, Kamei J. Olanzapine-induced hyperglycemia: possible involvement of histaminergic, dopaminergic and adrenergic functions in the central nervous system. Neuroendocrinology 2013; 98:224-32. [PMID: 24135197 DOI: 10.1159/000356119] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 09/29/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS Atypical antipsychotic drugs such as olanzapine are known to induce metabolic disturbance. We have already shown that olanzapine induces hepatic glucose production through the activation of hypothalamic adenosine 5'-monophosphate-activated protein kinase (AMPK). However, it is unclear how olanzapine activates hypothalamic AMPK. Since olanzapine is known to antagonize several receptors, including histaminergic, muscarinic, serotonergic, dopaminergic and adrenergic receptors, we examined the effect of each receptor antagonist on blood glucose levels in mice. Moreover, we also investigated whether these antagonists activate hypothalamic AMPK. METHODS Male 6-week-old ICR mice were used. Blood glucose levels were determined by the glucose oxidase method. AMPK expression was measured by Western blotting. RESULTS Central administration of olanzapine (5-15 nmol i.c.v.) dose-dependently increased blood glucose levels in mice, whereas olanzapine did not change blood insulin levels. Histamine H1 receptor antagonist chlorpheniramine (1-10 μg i.c.v.), dopamine D2 receptor antagonist L-sulpiride (1-10 μg i.c.v.) and α1-adrenoceptor antagonist prazosin (0.3-3 μg i.c.v.) also significantly increased blood glucose levels in mice. In contrast, the blood glucose levels were not affected by muscarinic M1 receptor antagonist dicyclomine (1-10 μg i.c.v.) or serotonin 5-HT2A receptor antagonist M100907 (1-10 ng i.c.v.). Olanzapine-induced hyperglycemia was inhibited by the AMPK inhibitor compound C, and AMPK activator AICAR (10 ng to 1 μg i.c.v.) significantly increased blood glucose levels. Olanzapine (15 nmol), chlorpheniramine (10 μg), L-sulpiride (10 μg) and prazosin (3 μg) significantly increased phosphorylated AMPK in the hypothalamus of mice. CONCLUSION These results suggest that olanzapine activates hypothalamic AMPK by antagonizing histamine H1 receptors, dopamine D2 receptors and α1-adrenoceptors, which induces hyperglycemia.
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Affiliation(s)
- Megumi Ikegami
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan
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Kaidanovich-Beilin O, Cha DS, McIntyre RS. Crosstalk between metabolic and neuropsychiatric disorders. F1000 BIOLOGY REPORTS 2012; 4:14. [PMID: 22802875 PMCID: PMC3388805 DOI: 10.3410/b4-14] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Evidence supporting the concurrence of metabolic disturbances (e.g. insulin resistance, diabetes and obesity) and neuropsychiatric disorders has been demonstrated in both human and animal studies, suggesting the possibility that they have shared pathophysiological mechanisms. During the past decade, our understanding for the role of insulin in both normal and abnormal central nervous system (CNS) processes has become increasingly refined. Evidence indicates that insulin is a pleiotropic peptide, critical to neurotrophism, neuroplasticity, and neuromodulation. Moreover, the role of insulin underscores its importance in the development of several neuropsychiatric disorders, including, but not limited to, mechanisms involved in the pathogenesis and progression towards diabetes, obesity, and neurodegenerative disorders, such as Alzheimer's disease. This review focuses on the insulin-mediated effects on normal and abnormal brain function and discusses why targeting insulin-related pathways in the brain may emerge as a new approach for refining treatment of neurological and psychiatric disorders.
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Affiliation(s)
- Oksana Kaidanovich-Beilin
- Samuel Lunenfeld Research InstituteMount Sinai Hospital, 600 University Avenue, Room 983, Toronto, Ontario, M5G 1X5Canada
| | - Danielle S. Cha
- Department of Psychiatry, University of Toronto, and the Mood Disorders Psychopharmacology Unit, University Health Network399 Bathurst Street, MP 9-325, Toronto, Ontario, M5T 2S8Canada
| | - Roger S. McIntyre
- Department of Psychiatry, University of Toronto, and the Mood Disorders Psychopharmacology Unit, University Health Network399 Bathurst Street, MP 9-325, Toronto, Ontario, M5T 2S8Canada
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Gibson CD, Karmally W, McMahon DJ, Wardlaw SL, Korner J. Randomized pilot study of cabergoline, a dopamine receptor agonist: effects on body weight and glucose tolerance in obese adults. Diabetes Obes Metab 2012; 14:335-40. [PMID: 22074059 PMCID: PMC3290696 DOI: 10.1111/j.1463-1326.2011.01534.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM Dopaminergic hypofunction and hyperprolactinaemia have been implicated in the pathogenesis of obesity and glucose intolerance. The aim of this pilot study was to determine the efficacy of cabergoline, a dopamine receptor agonist, on body weight and glucose tolerance in obese non-diabetic persons with normal plasma prolactin levels. METHODS This 16-week double blind, placebo-controlled pilot study randomized non-diabetic obese adults (body mass index 30-42 kg/m(2) ) to placebo or cabergoline (0.25 mg twice weekly for 4 weeks followed by 0.5 mg twice weekly for the next 12 weeks). Of 40 subjects enrolled, 29 completed 16 weeks: 16 randomized to placebo and 13 to cabergoline. All subjects were counselled on a 500 kcal/day calorie deficit diet. A 75-g oral glucose tolerance test was performed at baseline and at 16 weeks. RESULTS As expected, prolactin levels decreased after cabergoline (p < 0.001). Weight loss was similar after placebo compared with cabergoline treatment: 1.0 vs. 1.2% body weight, respectively. Fasting glucose levels did not differ between groups after treatment, however, 90-min postprandial glucose and insulin decreased in the cabergoline group only (p = 0.029). HOMA-IR (homeostasis model of assessment) increased by 40% after placebo and 1.5% after cabergoline treatment. CONCLUSIONS This pilot study suggests that cabergoline therapy may improve glucose tolerance independent of weight loss, however, a larger, longer term study of dopamine receptor agonist therapy in obese individuals is warranted to confirm this finding.
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Affiliation(s)
- Charlisa D. Gibson
- Department of Medicine, New York Obesity Research Center, St. Luke’s-Roosevelt Hospital Center New York, New York
| | - Wahida Karmally
- Irving Institute for Clinical and Translational Research, Columbia University, New York, New York
| | - Donald J. McMahon
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York
| | - Sharon L. Wardlaw
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York
| | - Judith Korner
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York
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Abstract
A placebo-controlled prospective safety study of quick-release bromocriptine in patients with type 2 diabetes has shown a 40% reduction in cardiovascular events. Possible explanations for this decrease are that through re-establishing diurnal variation a decrease in insulin resistance and its associated risk factors occurs. In addition, a decrease in the activity of the sympathetic nervous and renin-angiotensin systems and re-establishment of diurnal variations in the pituitary-adrenal axis may play a role. However, the most probable explanation is that because of the lowering of insulin resistance there are decreases in hepatic glucose production and an increased uptake of glucose leading to decreased levels of postprandial glucose, free fatty acids and triglycerides, which cause decreases in inflammation, oxidative stress and accumulation of atheroma.
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Affiliation(s)
- D S H Bell
- University of Alabama-Birmingham, Southside Endocrinology, Birmingham, AL 35205, USA.
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Abstract
The central nervous system (CNS), generally accepted to regulate energy homeostasis, has been implicated in the metabolic perturbations that either cause or are associated with obesity. Normally, the CNS receives hormonal, metabolic, and neuronal input to assure adequate energy levels and maintain stable energy homeostasis. Recent evidence also supports that the CNS uses these same inputs to regulate glucose homeostasis and this aspect of CNS regulation also becomes impaired in the face of dietary-induced obesity. This review focuses on the literature surrounding hypothalamic regulation of energy and glucose homeostasis and discusses how dysregulation of this system may contribute to obesity and T2DM.
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Abstract
Bromocriptine mesylate quick-release was approved by the Food and Drug Administration (FDA) in May 2009, for the treatment of type 2 diabetes. Bromocriptine is thought to act on the circadian neuronal activities in the hypothalamus, to reset an abnormally elevated hypothalamic drive for increased plasma glucose, free fatty acids, and triglycerides in insulin-resistant patients. Randomized controlled trials have shown that bromocriptine-QR lowers glycated hemoglobin by 0.4 - 0.8% either as monotherapy or in combination with other anti-diabetes medications. The doses used to treat diabetes (up to 4.8 mg daily) are much lower than those used to treat Parkinson's disease, and apart from nausea, the drug is well-tolerated. The novel mechanism of action, good side effect profile, and its effects to reduce cardiovascular event rates make it an attractive option for the treatment of type 2 diabetes.
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Affiliation(s)
- C. Shivaprasad
- Department of Endocrinology, M. S. Ramaiah Hospital, Bangalore, India
| | - Sanjay Kalra
- Department of Endocrinology, Bharti Hospital and BRIDE, Karnal, Haryana, India
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Pharmacological modulation of dopamine receptor D2-mediated transmission alters the metabolic phenotype of diet induced obese and diet resistant C57Bl6 mice. EXPERIMENTAL DIABETES RESEARCH 2011; 2011:928523. [PMID: 21603181 PMCID: PMC3096057 DOI: 10.1155/2011/928523] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 02/09/2011] [Indexed: 11/18/2022]
Abstract
High fat feeding induces a variety of obese and lean phenotypes in inbred rodents. Compared to Diet Resistant (DR) rodents, Diet Induced Obese (DIO) rodents are insulin resistant and have a reduced dopamine receptor D2 (DRD2) mediated tone. We hypothesized that this differing dopaminergic tone contributes to the distinct metabolic profiles of these animals.
C57Bl6 mice were classified as DIO or DR based on their weight gain during 10 weeks of high fat feeding. Subsequently DIO mice were treated with the DRD2 agonist bromocriptine and DR mice with the DRD2 antagonist haloperidol for 2 weeks.
Compared to DR mice, the bodyweight of DIO mice was higher and their insulin sensitivity decreased. Haloperidol treatment reduced the voluntary activity and energy expenditure of DR mice and induced insulin resistance in these mice. Conversely, bromocriptine treatment tended to reduce bodyweight and voluntary activity, and reinforce insulin action in DIO mice.
These results show that DRD2 activation partly redirects high fat diet induced metabolic anomalies in obesity-prone mice. Conversely, blocking DRD2 induces an adverse metabolic profile in mice that are inherently resistant to the deleterious effects of high fat food. This suggests that dopaminergic neurotransmission is involved in the control of metabolic phenotype.
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Affiliation(s)
- Ralph A. DeFronzo
- Diabetes Division, University of Texas Health Science Center, San Antonio, Texas
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de Leeuw van Weenen JE, Auvinen HE, Parlevliet ET, Coomans CP, Schröder-van der Elst JP, Meijer OC, Pijl H. Blocking dopamine D2 receptors by haloperidol curtails the beneficial impact of calorie restriction on the metabolic phenotype of high-fat diet induced obese mice. J Neuroendocrinol 2011; 23:158-67. [PMID: 21062378 DOI: 10.1111/j.1365-2826.2010.02092.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Calorie restriction is the most effective way of expanding life-span and decreasing morbidity. It improves insulin sensitivity and delays the age-related loss of dopamine receptor D(2) (DRD2) expression in the brain. Conversely, high-fat feeding is associated with obesity, insulin resistance and a reduced number of DRD2 binding sites. We hypothesised that the metabolic benefit of calorie restriction involves the preservation of appropriate DRD2 transmission. The food intake of wild-type C57Bl6 male mice was restricted to 60% of ad lib. intake while they were treated with the DRD2 antagonist haloperidol or vehicle using s.c. implanted pellets. Mice with ad lib. access to food receiving vehicle treatment served as controls. All mice received high-fat food throughout the experiment. After 10 weeks, an i.p. glucose tolerance test was performed and, after 12 weeks, a hyperinsulinaemic euglycaemic clamp. Hypothalamic DRD2 binding was also determined after 12 weeks of treatment. Calorie-restricted (CR) vehicle mice were glucose tolerant and insulin sensitive compared to ad lib. (AL) fed vehicle mice. CR mice treated with haloperidol were slightly heavier than vehicle treated CR mice. Haloperidol completely abolished the beneficial impact of calorie restriction on glucose tolerance and partly reduced the insulin sensitivity observed in CR vehicle mice. The metabolic differences between AL and CR vehicle mice were not accompanied by alterations in hypothalamic DRD2 binding. In conclusion, blocking DRD2 curtails the metabolic effects of calorie restriction. Although this suggests that the dopaminergic system could be involved in the metabolic benefits of calorie restriction, restricting access to high-fat food does not increase (hypothalamic) DRD2 binding capacity, which argues against this inference.
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Affiliation(s)
- J E de Leeuw van Weenen
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Centre, Leiden, The Netherlands
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Humphreys MH, Ni XP, Pearce D. Cardiovascular effects of melanocortins. Eur J Pharmacol 2011; 660:43-52. [PMID: 21199648 DOI: 10.1016/j.ejphar.2010.10.102] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 10/02/2010] [Accepted: 10/12/2010] [Indexed: 01/04/2023]
Abstract
Melanocortins (MSH's) are three structurally related peptides derived from proopiomelanocortin. They regulate several physiologic functions including energy metabolism, appetite, and inflammation. Recent work in rodents has also identified important effects of MSH's, particularly γ-MSH, on sodium metabolism and blood pressure regulation. Normal rats and mice respond to a high sodium diet with an increase in the plasma concentration of γ-MSH, and remain normotensive, while those with genetic or pharmacologic γ-MSH deficiency become hypertensive on a high sodium diet. This hypertension is corrected by exogenous administration of the peptide. Mice lacking the γ-MSH receptor (the melanocortin 3 receptor, Mc3r) also become hypertensive on a high sodium diet but remain so when administered γ-MSH, and infusions of physiologic levels of the peptide stimulate urinary sodium excretion in normal rats and mice, but not in mice with deletion of Mc3r. The salt-sensitive hypertension in rodents with impaired γ-MSH signaling appears due to stimulation of noradrenergic activity, since plasma noradrenaline is increased and the hypertension is rapidly corrected with infusion of the α-adrenoceptor antagonist phentolamine. In contrast to the antihypertensive property of physiologic levels of γ-MSH, intravenous or intracerebroventricular injections of high levels of the peptide raise blood pressure. This occurs in mice lacking Mc3r, indicating an interaction with some other central receptor. Finally, the salt-sensitive hypertension in rodents with disruption of γ-MSH signaling is accompanied by insulin resistance, an observation which offers a new window into the study of the association of salt-sensitive hypertension with insulin resistance and type II diabetes.
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Affiliation(s)
- Michael H Humphreys
- Division of Nephrology, San Francisco General Hospital and Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA.
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43
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Abstract
Bromocriptine is an ergot alkaloid dopamine D(2) receptor agonist that has been used extensively in the past to treat hyperprolactinaemia, galactorrhoea and Parkinsonism. It is known that hypothalamic hypodopaminergic states and disturbed circadian rhythm are associated with the development of insulin resistance, obesity and diabetes in animals and humans. When administered in the early morning at the start of the light phase, a new quick release (QR) formulation of bromocriptine appears to act centrally to reset circadian rhythms of hypothalamic dopamine and serotonin and improve insulin resistance and other metabolic abnormalities. Phase II and III clinical studies show that QR-bromocriptine lowers glycated haemoglobin by 0.6-1.2% (7-13 mmol/mol) either as monotherapy or in combination with other antidiabetes medications. Apart from nausea, the drug is well tolerated. The doses used to treat diabetes (up to 4.8 mg daily) are much lower than those used to treat Parkinson's disease and have not been associated with retroperitoneal fibrosis or heart valve abnormalities. QR-bromocriptine (Cycloset™) has recently been approved in the USA for the treatment of type 2 diabetes mellitus (T2DM). Thus, a QR formulation of bromocriptine timed for peak delivery in the early morning may provide a novel neurally mediated approach to the control of hyperglycaemia in T2DM.
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Affiliation(s)
- R I G Holt
- Endocrinology and Metabolism Sub-division, Developmental Origins of Adult Health and Disease Division, University of Southampton School of Medicine, Southampton, UK.
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Gaziano JM, Cincotta AH, O'Connor CM, Ezrokhi M, Rutty D, Ma ZJ, Scranton RE. Randomized clinical trial of quick-release bromocriptine among patients with type 2 diabetes on overall safety and cardiovascular outcomes. Diabetes Care 2010; 33:1503-8. [PMID: 20332352 PMCID: PMC2890350 DOI: 10.2337/dc09-2009] [Citation(s) in RCA: 158] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 03/16/2010] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Quick-release bromocriptine (bromocriptine-QR), a D2 dopamine receptor agonist, is indicated as a treatment for type 2 diabetes. The Cycloset Safety Trial, a 52-week, randomized, double-blind, multicenter trial, evaluated the overall safety and cardiovascular safety of this novel therapy for type 2 diabetes. RESEARCH DESIGN AND METHODS A total of 3,095 patients with type 2 diabetes were randomized 2:1 to bromocriptine-QR or placebo in conjunction with the patient's usual diabetes therapy (diet controlled only or up to two antidiabetes medications, including insulin). The all-cause-safety end point was the occurrence of any serious adverse event (SAE), with a hazard ratio (HR) noninferiority margin of 1.5. In a prespecified analysis, the frequency of cardiovascular disease (CVD) events defined as a composite of myocardial infarction, stroke, coronary revascularization, and hospitalization for angina or congestive heart failure was evaluated using modified intent-to-treat analysis (clinicaltrials.gov, NCT00377676). RESULTS In the bromocriptine-QR group, 176 (8.6%) people reported SAEs compared with 98 (9.6%) in the placebo group (HR 1.02 [96% one-sided CI 1.27]). Fewer people reported a CVD end point in the bromocriptine-QR group versus the placebo group (37 [1.8%] vs. 32 [3.2%], respecively) (HR 0.60 [95% two-sided CI 0.35-0.96]). Nausea was the most commonly reported adverse event in the bromocriptine-QR group. CONCLUSIONS The frequency of SAEs was comparable between the treatment arms. Compared with patients in the placebo arm, fewer patients taking bromocriptine-QR experienced a cardiovascular end point.
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Affiliation(s)
- J Michael Gaziano
- Massachusetts Veterans Epidemiology Research and Information Center/VA Cooperative Studies Programs, VA Boston Healthcare System, Boston, Massachusetts, USA.
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Scranton R, Cincotta A. Bromocriptine--unique formulation of a dopamine agonist for the treatment of type 2 diabetes. Expert Opin Pharmacother 2010; 11:269-79. [PMID: 20030567 DOI: 10.1517/14656560903501544] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
IMPORTANCE TO THE FIELD There is a large unmet need for new therapies to treat type 2 diabetes (T2DM) which reduce fasting and postprandial glucose without increasing insulin levels and which are not associated with weight gain or hypoglycemia. The quick-release formulation of bromocriptine (bromocriptine-QR; Cycloset) represents such a therapy. AREAS COVERED IN THE REVIEW Bromocriptine-QR's proposed mechanism of action, unique formulation and clinical efficacy and safety will be discussed. A Medline search was conducted using the terms: bromocriptine quick-release, circadian rhythms, treatment type 2 diabetes, insulin resistance, beta-cell dysfunction (years 1985 - 2009). WHAT THE READER WILL GAIN The reader will gain an understanding of the importance of the brain as a target for the treatment of type 2 diabetes. In addition the safety, efficacy and indication for use of a first-in-class dopamine agonist as a treatment option for type 2 diabetes are discussed. TAKE HOME MESSAGE Bromocriptine-QR is indicated to be used alone or in conjunction with all available treatments for type 2 diabetes. Although the mechanism of action is not fully understood, bromocriptine-QR's action points to a central target in the brain (hypothalamus) which may explain the observed peripheral improvements in metabolic parameters.
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Cardoso S, Santos R, Correia S, Carvalho C, Zhu X, Lee HG, Casadesus G, Smith MA, Perry G, Moreira PI. Insulin and Insulin-Sensitizing Drugs in Neurodegeneration: Mitochondria as Therapeutic Targets. Pharmaceuticals (Basel) 2009; 2:250-286. [PMID: 27713238 PMCID: PMC3978547 DOI: 10.3390/ph2030250] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 12/21/2009] [Accepted: 12/22/2009] [Indexed: 12/13/2022] Open
Abstract
Insulin, besides its glucose lowering effects, is involved in the modulation of lifespan, aging and memory and learning processes. As the population ages, neurodegenerative disorders become epidemic and a connection between insulin signaling dysregulation, cognitive decline and dementia has been established. Mitochondria are intracellular organelles that despite playing a critical role in cellular metabolism are also one of the major sources of reactive oxygen species. Mitochondrial dysfunction, oxidative stress and neuroinflammation, hallmarks of neurodegeneration, can result from impaired insulin signaling. Insulin-sensitizing drugs such as the thiazolidinediones are a new class of synthetic compounds that potentiate insulin action in the target tissues and act as specific agonists of the peroxisome proliferator-activated receptor gamma (PPAR-γ). Recently, several PPAR agonists have been proposed as novel and possible therapeutic agents for neurodegenerative disorders. Indeed, the literature shows that these agents are able to protect against mitochondrial dysfunction, oxidative damage, inflammation and apoptosis. This review discusses the role of mitochondria and insulin signaling in normal brain function and in neurodegeneration. Furthermore, the potential protective role of insulin and insulin sensitizers in Alzheimer´s, Parkinson´s and Huntington´s diseases and amyotrophic lateral sclerosis will be also discussed.
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Affiliation(s)
- Susana Cardoso
- Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra, Portugal
- Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3000- 354 Coimbra, Portugal
| | - Renato Santos
- Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra, Portugal
- Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3000- 354 Coimbra, Portugal
| | - Sonia Correia
- Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra, Portugal
- Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3000- 354 Coimbra, Portugal
| | - Cristina Carvalho
- Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra, Portugal
- Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3000- 354 Coimbra, Portugal
| | - Xiongwei Zhu
- School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Hyoung-Gon Lee
- School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Gemma Casadesus
- School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Mark A Smith
- School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - George Perry
- College of Sciences, The University of Texas at San Antonio, TX 78249, USA
| | - Paula I Moreira
- Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra, Portugal.
- Institute of Physiology, Faculty of Medicine, University of Coimbra, 3000-354 Coimbra, Portugal.
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D'Amelio M, Ragonese P, Callari G, Di Benedetto N, Palmeri B, Terruso V, Salemi G, Famoso G, Aridon P, Savettieri G. Diabetes preceding Parkinson's disease onset. A case–control study. Parkinsonism Relat Disord 2009; 15:660-4. [DOI: 10.1016/j.parkreldis.2009.02.013] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 02/23/2009] [Accepted: 02/27/2009] [Indexed: 10/20/2022]
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Ni XP, van Dijk C, Pearce D, Humphreys MH. Evidence for a noradrenergic mechanism causing hypertension and abnormal glucose metabolism in rats with relative deficiency of gamma-melanocyte-stimulating hormone. Exp Physiol 2009; 94:867-76. [PMID: 19429645 DOI: 10.1113/expphysiol.2009.046748] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A close association between salt-sensitive hypertension and insulin resistance has been recognized for more than two decades, although the mechanism(s) underlying this relationship have not been elucidated. Recent data in mice with genetic disruption of the gamma-melanocyte-stimulating hormone (gamma-MSH) system suggest that this system plays a role in the pathophysiological relationship between hypertension and altered glucose metabolism during ingestion of a high-sodium diet (8% NaCl, HSD). We tested the hypothesis that these two consequences of interrupted gamma-MSH signalling were the result of sympathetic activation by studying rats treated with the dopaminergic agonist bromocriptine (5 mg kg(-1) i.p., daily for 1 week; Bromo) to cause relative gamma-MSH deficiency. Bromo-treated rats fed the HSD developed hypertension and also exhibited fasting hyperglycaemia (P < 0.005) and hyperinsulinaemia (P < 0.025). Furthermore, Bromo-treated rats on the HSD had impaired glucose tolerance and blunted insulin-mediated glucose disposal. Intravenous infusion of gamma(2)-MSH, or of the alpha-adrenergic receptor antagonist phentolamine, to Bromo-HSD rats lowered both mean arterial pressure (MAP) and blood glucose to normal after 15 min (P < 0.001 versus control), but had no effect in rats receiving vehicle and fed the HSD; gamma(2)-MSH infusion also reduced the elevated plasma noradrenaline to control levels in parallel with the reductions in MAP and blood glucose concentration. Infusion of hydralazine to Bromo-HSD rats lowered MAP but had only a trivial effect on blood glucose. We conclude that rats with relative gamma-MSH deficiency develop abnormal glucose metabolism, with features of insulin resistance, in association with hypertension when ingesting the HSD. Elevated plasma noradrenaline concentration in Bromo-HSD rats is normalized by gamma(2)-MSH infusion, suggesting that an adrenergic mechanism may link the salt-sensitive hypertension and the impaired glucose metabolism of relative gamma-MSH deficiency.
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Affiliation(s)
- Xi-Ping Ni
- Division of Nephrology, San Francisco General Hospital and Department of Medicine, University of California San Francisco, San Francisco, CA 94143-1341, USA
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de Leeuw van Weenen JE, Hu L, Jansen-Van Zelm K, de Vries MG, Tamsma JT, Romijn JA, Pijl H. Four weeks high fat feeding induces insulin resistance without affecting dopamine release or gene expression patterns in the hypothalamus of C57Bl6 mice. Brain Res 2008; 1250:141-8. [PMID: 19028458 DOI: 10.1016/j.brainres.2008.11.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 10/02/2008] [Accepted: 11/02/2008] [Indexed: 11/16/2022]
Abstract
Obesity is associated with diminished dopaminergic neurotransmission. It remains unclear whether this is a cause or a consequence of the obese state. We hypothesized that high fat feeding, a well known trigger of obesity in diet sensitive mice, would blunt dopaminergic neurotransmission prior to the development of insulin resistance. We monitored in vivo dopamine release in the dorsomedial region of the hypothalamus, and determined hypothalamic gene expression patterns of dopamine receptors 1 and 2 (DRD1 and 2), tyrosine hydroxylase (TH) and the dopamine transporter (DAT) in C57Bl6 mice maintained on a high fat diet for 4 weeks. Also, a hyperinsulinemic euglycemic clamp was performed to evaluate the metabolic status of the mice. Mice maintained on a low fat diet served as controls. The high fat diet did not alter dopamine release in the dorsomedial hypothalamus of fed or fasted mice or the dopaminergic response to refeeding. Furthermore, gene expression levels of DRD1, DRD2, TH and DAT were not affected by high fat feeding. However, the high fat diet did hamper insulin action as evidenced by diminished glucose disposal during hyperinsulinemia (p<0.05). We show here that short term high fat feeding does not affect dopaminergic neurotransmission in the hypothalamus, whereas it does impair insulin action. This suggests that reduced dopaminergic neurotransmission in the hypothalamus of obese animal models is due to mechanism(s) that are not directly triggered by diet composition.
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Affiliation(s)
- J E de Leeuw van Weenen
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands.
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Becker C, Brobert GP, Johansson S, Jick SS, Meier CR. Diabetes in patients with idiopathic Parkinson's disease. Diabetes Care 2008; 31:1808-12. [PMID: 18559656 PMCID: PMC2518349 DOI: 10.2337/dc08-0479] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Previous observational studies reported inconsistent results on the association between diabetes and Parkinson's disease, and data on the risk of developing incident diabetes in relation to Parkinson's disease are scarce. We aimed at comparing the diabetes prevalence between patients with or without Parkinson's disease and at exploring the risk of developing incident diabetes associated with Parkinson's disease. RESEARCH DESIGN AND METHODS We used the U.K.-based General Practice Research Database (GPRD) to 1) compare the diabetes prevalence between Parkinson's disease cases and a matched comparison group free of Parkinson's disease between 1994 and 2005 and to 2) conduct a follow-up study with a nested case-control analysis to quantify the risk of developing new-onset diabetes in association with Parkinson's disease. RESULTS The diabetes prevalence was similar in patients with and without Parkinson's disease (adjusted odds ratio [OR] 0.95 [95% CI 0.80-1.14]). In the cohort analysis (incidence rate ratio [IRR] 0.55 [95% CI 0.38-0.81]) and in the nested case-control analysis (adjusted OR 0.53 [95% CI 0.33-0.87]), the risk of developing diabetes was lower in patients with Parkinson's disease than in subjects without. The adjusted OR for patients with Parkinson's disease who were current levodopa users of five or more prescriptions was 0.22 (0.10-0.48) and was 1.11 (0.50-2.45) for Parkinson's disease patients not using levodopa. CONCLUSIONS In this observational study, diabetes prevalence was closely similar between patients with Parkinson's disease and subjects without. The risk of developing incident diabetes was lower for patients with Parkinson's disease than for patients without, a finding that was limited to Parkinson's disease patients who were using levodopa.
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Affiliation(s)
- Claudia Becker
- Basel Pharmacoepidemiology Unit, Division of Clinical Pharmacology and Toxicology, University Hospital, Basel, Switzerland
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