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Li Z, Zheng L, Wang J, Wang L, Qi Y, Amin B, Zhu J, Zhang N. Dopamine in the regulation of glucose and lipid metabolism: a narrative review. Obesity (Silver Spring) 2024; 32:1632-1645. [PMID: 39081007 DOI: 10.1002/oby.24068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 04/16/2024] [Accepted: 04/19/2024] [Indexed: 08/29/2024]
Abstract
OBJECTIVE Owing to the global obesity epidemic, understanding the regulatory mechanisms of glucose and lipid metabolism has become increasingly important. The dopaminergic system, including dopamine, dopamine receptors, dopamine transporters, and other components, is involved in numerous physiological and pathological processes. However, the mechanism of action of the dopaminergic system in glucose and lipid metabolism is poorly understood. In this review, we examine the role of the dopaminergic system in glucose and lipid metabolism. RESULTS The dopaminergic system regulates glucose and lipid metabolism through several mechanisms. It regulates various activities at the central level, including appetite control and decision-making, which contribute to regulating body weight and energy metabolism. In the pituitary gland, dopamine inhibits prolactin production and promotes insulin secretion through dopamine receptor 2. Furthermore, it can influence various physiological components in the peripheral system, such as pancreatic β cells, glucagon-like peptide-1, adipocytes, hepatocytes, and muscle, by regulating insulin and glucagon secretion, glucose uptake and use, and fatty acid metabolism. CONCLUSIONS The role of dopamine in regulating glucose and lipid metabolism has significant implications for the physiology and pathogenesis of disease. The potential therapeutic value of dopamine lies in its effects on metabolic disorders.
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Affiliation(s)
- Zhehong Li
- Surgery Centre of Diabetes Mellitus, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
- Department of General Surgery, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Lifei Zheng
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Jing Wang
- Surgery Centre of Diabetes Mellitus, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
- Department of General Surgery, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Liang Wang
- Surgery Centre of Diabetes Mellitus, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
- Department of General Surgery, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Yao Qi
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Buhe Amin
- Surgery Centre of Diabetes Mellitus, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
- Department of General Surgery, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Jinxia Zhu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Nengwei Zhang
- Surgery Centre of Diabetes Mellitus, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
- Department of General Surgery, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
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2
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Sternberg Z. Neurodegenerative Etiology of Aromatic L-Amino Acid Decarboxylase Deficiency: a Novel Concept for Expanding Treatment Strategies. Mol Neurobiol 2024; 61:2996-3018. [PMID: 37953352 DOI: 10.1007/s12035-023-03684-2] [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: 02/07/2023] [Accepted: 09/29/2023] [Indexed: 11/14/2023]
Abstract
Aromatic l-amino acid decarboxylase deficiency (AADC-DY) is caused by one or more mutations in the DDC gene, resulting in the deficit in catecholamines and serotonin neurotransmitters. The disease has limited therapeutic options with relatively poor clinical outcomes. Accumulated evidence suggests the involvement of neurodegenerative mechanisms in the etiology of AADC-DY. In the absence of neurotransmitters' neuroprotective effects, the accumulation and the chronic presence of several neurotoxic metabolites including 4-dihydroxy-L-phenylalanine, 3-methyldopa, and homocysteine, in the brain of subjects with AADC-DY, promote oxidative stress and reduce the cellular antioxidant and methylation capacities, leading to glial activation and mitochondrial dysfunction, culminating to neuronal injury and death. These pathophysiological processes have the potential to hinder the clinical efficacy of treatments aimed at increasing neurotransmitters' synthesis and or function. This review describes in detail the mechanisms involved in AADC-DY neurodegenerative etiology, highlighting the close similarities with those involved in other neurodegenerative diseases. We then offer novel strategies for the treatment of the disease with the objective to either reduce the level of the metabolites or counteract their prooxidant and neurotoxic effects. These treatment modalities used singly or in combination, early in the course of the disease, will minimize neuronal injury, preserving the functional integrity of neurons, hence improving the clinical outcomes of both conventional and unconventional interventions in AADC-DY. These modalities may not be limited to AADC-DY but also to other metabolic disorders where a specific mutation leads to the accumulation of prooxidant and neurotoxic metabolites.
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Affiliation(s)
- Zohi Sternberg
- Jacobs School of Medicine and Biomedical Sciences, Buffalo Medical Center, Buffalo, NY, 14203, USA.
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3
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Bonifazi A, Ellenberger M, Farino ZJ, Aslanoglou D, Rais R, Pereira S, Mantilla-Rivas JO, Boateng CA, Eshleman AJ, Janowsky A, Hahn MK, Schwartz GJ, Slusher BS, Newman AH, Freyberg Z. Development of novel tools for dissection of central versus peripheral dopamine D 2-like receptor signaling in dysglycemia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.21.581451. [PMID: 38529497 PMCID: PMC10962703 DOI: 10.1101/2024.02.21.581451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
Dopamine (DA) D2-like receptors in both the central nervous system (CNS) and the periphery are key modulators of metabolism. Moreover, disruption of D2-like receptor signaling is implicated in dysglycemia. Yet, the respective metabolic contributions of CNS versus peripheral D2-like receptors including D2 (D2R) and D3 (D3R) receptors remain poorly understood. To address this, we developed new pharmacological tools, D2-like receptor agonists with diminished and delayed blood-brain barrier capability, to selectively manipulate D2R/D3R signaling in the periphery. We designated bromocriptine methiodide (BrMeI), a quaternary methiodide analogue of D2/3R agonist and diabetes drug bromocriptine, as our lead compound based on preservation of D2R/D3R binding and functional efficacy. We then used BrMeI and unmodified bromocriptine to dissect relative contributions of CNS versus peripheral D2R/D3R signaling in treating dysglycemia. Systemic administration of bromocriptine, with unrestricted access to CNS and peripheral targets, significantly improved both insulin sensitivity and glucose tolerance in obese, dysglycemic mice in vivo. In contrast, metabolic improvements were attenuated when access to bromocriptine was restricted either to the CNS through intracerebroventricular administration or delayed access to the CNS via BrMeI. Our findings demonstrate that the coordinated actions of both CNS and peripheral D2-like receptors are required for correcting dysglycemia. Ultimately, the development of a first-generation of drugs designed to selectively target the periphery provides a blueprint for dissecting mechanisms of central versus peripheral DA signaling and paves the way for novel strategies to treat dysglycemia.
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Affiliation(s)
- Alessandro Bonifazi
- Medicinal Chemistry Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Michael Ellenberger
- Medicinal Chemistry Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Zachary J. Farino
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Rana Rais
- Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sandra Pereira
- Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | | | - Comfort A. Boateng
- Medicinal Chemistry Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Amy J. Eshleman
- Research Service, VA Portland Health Care System, Portland, Oregon, USA
- Departments of Behavioral Neuroscience and Psychiatry, Oregon Health & Science University, Portland, OR, USA
| | - Aaron Janowsky
- Research Service, VA Portland Health Care System, Portland, Oregon, USA
- Departments of Behavioral Neuroscience and Psychiatry, Oregon Health & Science University, Portland, OR, USA
- Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, USA
| | - Margaret K. Hahn
- Centre for Addiction and Mental Health, Toronto, ON, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
- Department of Pharmacology, University of Toronto, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Banting & Best Diabetes Centre, Toronto, ON, Canada
| | - Gary J. Schwartz
- The Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, USA
- Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Barbara S. Slusher
- Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Amy Hauck Newman
- Medicinal Chemistry Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Zachary Freyberg
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
- Lead Contact
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4
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Vranic M, Ahmed F, Kristófi R, Hetty S, Mokhtari D, Svensson MK, Eriksson JW, Pereira MJ. Subcutaneous adipose tissue dopamine D2 receptor is increased in prediabetes and T2D. Endocrine 2024; 83:378-391. [PMID: 37752366 PMCID: PMC10850013 DOI: 10.1007/s12020-023-03525-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 09/06/2023] [Indexed: 09/28/2023]
Abstract
PURPOSE To evaluate the dopaminergic signaling in human adipose tissue in the context of obesity and type 2 diabetes (T2D) and potential direct implications in adipose tissue metabolism. METHODS mRNA and protein expression of dopamine receptors D1 and D2 (DRD1 and DRD2) were determined in subcutaneous adipose tissue from subjects without or with T2D and with different body weight, and correlated with markers of obesity, hyperglycemia, and insulin resistance. Glucose uptake and lipolysis were measured in adipocytes ex vivo following short-term exposure to dopamine, DRD1 receptor agonist (SKF81297), or DRD2 receptor agonist (bromocriptine). RESULTS DRD1 and DRD2 gene expression in subcutaneous adipose tissue correlated positively with clinical markers of insulin resistance (e.g. HOMA-IR, insulin, and triglycerides) and central obesity in subjects without T2D. Protein expression of DRD2 in subcutaneous adipose tissue, but not DRD1, is higher in subjects with impaired fasting glucose and T2D and correlated positively with hyperglycemia, HbA1c, and glucose AUC, independent of obesity status. DRD1 and DRD2 proteins were mainly expressed in adipocytes, compared to stromal vascular cells. Dopamine and dopaminergic agonists did not affect adipocyte glucose uptake ex vivo, but DRD1 and DRD2 agonist treatment inhibited isoproterenol-stimulated lipolysis. CONCLUSION The results suggest that protein expression of DRD2 in subcutaneous adipose tissue is up-regulated with hyperglycemia and T2D. Whether DRD2 protein levels contribute to T2D development or occur as a secondary compensatory mechanism needs further investigation. Additionally, dopamine receptor agonists inhibit adipocyte beta-adrenergic stimulation of lipolysis, which might contribute to the beneficial effects in lipid metabolism as observed in patients taking bromocriptine.
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Affiliation(s)
- Milica Vranic
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Fozia Ahmed
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Robin Kristófi
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Susanne Hetty
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Dariush Mokhtari
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Maria K Svensson
- Department of Medical Sciences, Renal Medicine, Uppsala University, Uppsala, Sweden
| | - Jan W Eriksson
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Maria J Pereira
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden.
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5
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Cincotta AH. Brain Dopamine-Clock Interactions Regulate Cardiometabolic Physiology: Mechanisms of the Observed Cardioprotective Effects of Circadian-Timed Bromocriptine-QR Therapy in Type 2 Diabetes Subjects. Int J Mol Sci 2023; 24:13255. [PMID: 37686060 PMCID: PMC10487918 DOI: 10.3390/ijms241713255] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/19/2023] [Accepted: 07/27/2023] [Indexed: 09/10/2023] Open
Abstract
Despite enormous global efforts within clinical research and medical practice to reduce cardiovascular disease(s) (CVD), it still remains the leading cause of death worldwide. While genetic factors clearly contribute to CVD etiology, the preponderance of epidemiological data indicate that a major common denominator among diverse ethnic populations from around the world contributing to CVD is the composite of Western lifestyle cofactors, particularly Western diets (high saturated fat/simple sugar [particularly high fructose and sucrose and to a lesser extent glucose] diets), psychosocial stress, depression, and altered sleep/wake architecture. Such Western lifestyle cofactors are potent drivers for the increased risk of metabolic syndrome and its attendant downstream CVD. The central nervous system (CNS) evolved to respond to and anticipate changes in the external (and internal) environment to adapt survival mechanisms to perceived stresses (challenges to normal biological function), including the aforementioned Western lifestyle cofactors. Within the CNS of vertebrates in the wild, the biological clock circuitry surveils the environment and has evolved mechanisms for the induction of the obese, insulin-resistant state as a survival mechanism against an anticipated ensuing season of low/no food availability. The peripheral tissues utilize fat as an energy source under muscle insulin resistance, while increased hepatic insulin resistance more readily supplies glucose to the brain. This neural clock function also orchestrates the reversal of the obese, insulin-resistant condition when the low food availability season ends. The circadian neural network that produces these seasonal shifts in metabolism is also responsive to Western lifestyle stressors that drive the CNS clock into survival mode. A major component of this natural or Western lifestyle stressor-induced CNS clock neurophysiological shift potentiating the obese, insulin-resistant state is a diminution of the circadian peak of dopaminergic input activity to the pacemaker clock center, suprachiasmatic nucleus. Pharmacologically preventing this loss of circadian peak dopaminergic activity both prevents and reverses existing metabolic syndrome in a wide variety of animal models of the disorder, including high fat-fed animals. Clinically, across a variety of different study designs, circadian-timed bromocriptine-QR (quick release) (a unique formulation of micronized bromocriptine-a dopamine D2 receptor agonist) therapy of type 2 diabetes subjects improved hyperglycemia, hyperlipidemia, hypertension, immune sterile inflammation, and/or adverse cardiovascular event rate. The present review details the seminal circadian science investigations delineating important roles for CNS circadian peak dopaminergic activity in the regulation of peripheral fuel metabolism and cardiovascular biology and also summarizes the clinical study findings of bromocriptine-QR therapy on cardiometabolic outcomes in type 2 diabetes subjects.
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6
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Civelek E, Ozturk Civelek D, Akyel YK, Kaleli Durman D, Okyar A. Circadian Dysfunction in Adipose Tissue: Chronotherapy in Metabolic Diseases. BIOLOGY 2023; 12:1077. [PMID: 37626963 PMCID: PMC10452180 DOI: 10.3390/biology12081077] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/26/2023] [Accepted: 07/28/2023] [Indexed: 08/27/2023]
Abstract
Essential for survival and reproduction, the circadian timing system (CTS) regulates adaptation to cyclical changes such as the light/dark cycle, temperature change, and food availability. The regulation of energy homeostasis possesses rhythmic properties that correspond to constantly fluctuating needs for energy production and consumption. Adipose tissue is mainly responsible for energy storage and, thus, operates as one of the principal components of energy homeostasis regulation. In accordance with its roles in energy homeostasis, alterations in adipose tissue's physiological processes are associated with numerous pathologies, such as obesity and type 2 diabetes. These alterations also include changes in circadian rhythm. In the current review, we aim to summarize the current knowledge regarding the circadian rhythmicity of adipogenesis, lipolysis, adipokine secretion, browning, and non-shivering thermogenesis in adipose tissue and to evaluate possible links between those alterations and metabolic diseases. Based on this evaluation, potential therapeutic approaches, as well as clock genes as potential therapeutic targets, are also discussed in the context of chronotherapy.
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Affiliation(s)
- Erkan Civelek
- Department of Pharmacology, Faculty of Pharmacy, Istanbul University, 34116 Istanbul, Turkey; (E.C.); (D.K.D.)
| | - Dilek Ozturk Civelek
- Department of Pharmacology, Faculty of Pharmacy, Bezmialem Vakıf University, 34093 Istanbul, Turkey;
| | - Yasemin Kubra Akyel
- Department of Medical Pharmacology, School of Medicine, Istanbul Medipol University, 34815 Istanbul, Turkey;
| | - Deniz Kaleli Durman
- Department of Pharmacology, Faculty of Pharmacy, Istanbul University, 34116 Istanbul, Turkey; (E.C.); (D.K.D.)
| | - Alper Okyar
- Department of Pharmacology, Faculty of Pharmacy, Istanbul University, 34116 Istanbul, Turkey; (E.C.); (D.K.D.)
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7
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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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8
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Analysis of the Relationship between Type II Diabetes Mellitus and Parkinson's Disease: A Systematic Review. PARKINSONS DISEASE 2019; 2019:4951379. [PMID: 31871617 PMCID: PMC6906831 DOI: 10.1155/2019/4951379] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 10/01/2019] [Accepted: 11/06/2019] [Indexed: 12/31/2022]
Abstract
In the early sixties, a discussion started regarding the association between Parkinson's disease (PD) and type II diabetes mellitus (T2DM). Today, this potential relationship is still a matter of debate. This review aims to analyze both diseases concerning causal relationships and treatments. A total of 104 articles were found, and studies on animal and “in vitro” models showed that T2DM causes neurological alterations that may be associated with PD, such as deregulation of the dopaminergic system, a decrease in the expression of peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α), an increase in the expression of phosphoprotein enriched in diabetes/phosphoprotein enriched in astrocytes 15 (PED/PEA-15), and neuroinflammation, as well as acceleration of the formation of alpha-synuclein amyloid fibrils. In addition, clinical studies described that Parkinson's symptoms were notably worse after the onset of T2DM, and seven deregulated genes were identified in the DNA of T2DM and PD patients. Regarding treatment, the action of antidiabetic drugs, especially incretin mimetic agents, seems to confer certain degree of neuroprotection to PD patients. In conclusion, the available evidence on the interaction between T2DM and PD justifies more robust clinical trials exploring this interaction especially the clinical management of patients with both conditions.
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Oshige T, Nakamura Y, Sasaki Y, Kawano S, Ohki T, Tsuruta M, Tokubuchi I, Nakayama H, Yamada K, Ashida K, Tajiri Y, Nomura M. Bromocriptine as a Potential Glucose-lowering Agent for the Treatment of Prolactinoma with Type 2 Diabetes. Intern Med 2019; 58:3125-3128. [PMID: 31243214 PMCID: PMC6875449 DOI: 10.2169/internalmedicine.2755-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A 22-year-old Japanese woman consulted an endocrinologist due to persistent galactorrhea for the past 10 months. She had hyperprolacinemia and had previously been diagnosed with type 2 diabetes mellitus based on her glycohemoglobin level of 11.6%. After two months, she was admitted to our hospital and finally diagnosed with prolactinoma. For the treatment of prolactinoma, bromocriptine 2.5 mg/day was started. After seven days, her post-prandial blood glucose levels, homeostasis model assessment of insulin resistance and plasma C-peptide levels were significantly improved. These results indicate that traditional bromocriptine can be an effective therapeutic alternative in patients with prolactinoma complicated with type 2 diabetes.
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Affiliation(s)
- Tamami Oshige
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, Japan
| | - Yui Nakamura
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, Japan
| | - Yuko Sasaki
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, Japan
| | - Seiko Kawano
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, Japan
| | - Tsuyoshi Ohki
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, Japan
| | - Munehisa Tsuruta
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, Japan
| | - Ichiro Tokubuchi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, Japan
| | - Hitomi Nakayama
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, Japan
| | | | - Kenji Ashida
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, Japan
| | - Yuji Tajiri
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, Japan
| | - Masatoshi Nomura
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, Japan
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10
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Fiory F, Perruolo G, Cimmino I, Cabaro S, Pignalosa FC, Miele C, Beguinot F, Formisano P, Oriente F. The Relevance of Insulin Action in the Dopaminergic System. Front Neurosci 2019; 13:868. [PMID: 31474827 PMCID: PMC6706784 DOI: 10.3389/fnins.2019.00868] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 08/02/2019] [Indexed: 12/13/2022] Open
Abstract
The advances in medicine, together with lifestyle modifications, led to a rising life expectancy. Unfortunately, however, aging is accompanied by an alarming boost of age-associated chronic pathologies, including neurodegenerative and metabolic diseases. Interestingly, a non-negligible interplay between alterations of glucose homeostasis and brain dysfunction has clearly emerged. In particular, epidemiological studies have pointed out a possible association between Type 2 Diabetes (T2D) and Parkinson’s Disease (PD). Insulin resistance, one of the major hallmark for etiology of T2D, has a detrimental influence on PD, negatively affecting PD phenotype, accelerating its progression and worsening cognitive impairment. This review aims to provide an exhaustive analysis of the most recent evidences supporting the key role of insulin resistance in PD pathogenesis. It will focus on the relevance of insulin in the brain, working as pro-survival neurotrophic factor and as a master regulator of neuronal mitochondrial function and oxidative stress. Insulin action as a modulator of dopamine signaling and of alpha-synuclein degradation will be described in details, too. The intriguing idea that shared deregulated pathogenic pathways represent a link between PD and insulin resistance has clinical and therapeutic implications. Thus, ongoing studies about the promising healing potential of common antidiabetic drugs such as metformin, exenatide, DPP IV inhibitors, thiazolidinediones and bromocriptine, will be summarized and the rationale for their use to decelerate neurodegeneration will be critically assessed.
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Affiliation(s)
- Francesca Fiory
- Department of Translational Medicine, University of Naples Federico II, Naples, Italy.,URT "Genomic of Diabetes," Institute of Experimental Endocrinology and Oncology, National Research Council, Naples, Italy
| | - Giuseppe Perruolo
- Department of Translational Medicine, University of Naples Federico II, Naples, Italy.,URT "Genomic of Diabetes," Institute of Experimental Endocrinology and Oncology, National Research Council, Naples, Italy
| | - Ilaria Cimmino
- Department of Translational Medicine, University of Naples Federico II, Naples, Italy.,URT "Genomic of Diabetes," Institute of Experimental Endocrinology and Oncology, National Research Council, Naples, Italy
| | - Serena Cabaro
- Department of Translational Medicine, University of Naples Federico II, Naples, Italy.,URT "Genomic of Diabetes," Institute of Experimental Endocrinology and Oncology, National Research Council, Naples, Italy
| | - Francesca Chiara Pignalosa
- Department of Translational Medicine, University of Naples Federico II, Naples, Italy.,URT "Genomic of Diabetes," Institute of Experimental Endocrinology and Oncology, National Research Council, Naples, Italy
| | - Claudia Miele
- Department of Translational Medicine, University of Naples Federico II, Naples, Italy.,URT "Genomic of Diabetes," Institute of Experimental Endocrinology and Oncology, National Research Council, Naples, Italy
| | - Francesco Beguinot
- Department of Translational Medicine, University of Naples Federico II, Naples, Italy.,URT "Genomic of Diabetes," Institute of Experimental Endocrinology and Oncology, National Research Council, Naples, Italy
| | - Pietro Formisano
- Department of Translational Medicine, University of Naples Federico II, Naples, Italy.,URT "Genomic of Diabetes," Institute of Experimental Endocrinology and Oncology, National Research Council, Naples, Italy
| | - Francesco Oriente
- Department of Translational Medicine, University of Naples Federico II, Naples, Italy.,URT "Genomic of Diabetes," Institute of Experimental Endocrinology and Oncology, National Research Council, Naples, Italy
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11
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Hassanabad MF, Fatehi M. Current Views on Dopaminergic Drugs Affecting Glucose Homeostasis. Curr Diabetes Rev 2019; 15:93-99. [PMID: 29692257 DOI: 10.2174/1573399814666180424123912] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 04/17/2018] [Accepted: 04/19/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND For more than three decades, it has been known that manipulation of dopaminergic system could affect glucose homesotasis in experimental animals. The notion that glucose homeostasis in human might be influenced by dopaminergic drugs has attracted a great deal of attention in the past two decades. In spite of rapid advancements in revealing involvement of dopaminergic neurotransmission in insulin release, glucose up-take and pancreatic beta cell function in general through centrally and peripherally controlled mechanisms, there are discrepancies among observations on experimental animals and human subjects. CONCLUSION With the expansion of pharmacotherapy in psychotic conditions, depression and endocrine abnormalities along with a sharp increase in prevalence of type two diabetes and disturbances of glucose homeostasis as a major risk factor for many cardiovascular complications and associated mortalities; it seems a critical analysis of recent investigations on drugs which act as agonists or antagonists of dopaminergic receptors in various tissues and organs may provide better insight into how safe and efficient these medicines could be prescribed. Furthermore, the other main objective of present review is to compare clinical data on significance of changes in blood glucose and insulin levels during short term and after long term treatment with these agents. This in turn would be beneficial for determining adequate strategies to combat or to avoid adverse effects associated with dopaminergic drug therapy.
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Affiliation(s)
- Mortaza Fatehi Hassanabad
- Department of Pharmacology, Alberta Diabetes Institute, Room 6-126 Li Ka Shing Centre for Health Research Innovation, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Mohammad Fatehi
- Department of Pharmacology, Alberta Diabetes Institute, Room 6-126 Li Ka Shing Centre for Health Research Innovation, University of Alberta, Edmonton, AB, T6G 2E1, Canada
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Alatrach M, Agyin C, Adams J, Chilton R, Triplitt C, DeFronzo RA, Cersosimo E. Glucose lowering and vascular protective effects of cycloset added to GLP-1 receptor agonists in patients with type 2 diabetes. Endocrinol Diabetes Metab 2018; 1:e00034. [PMID: 30815562 PMCID: PMC6354804 DOI: 10.1002/edm2.34] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 06/01/2018] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE To determine the glucose-lowering mechanism of action and the effects of a quick-release bromocriptine-QR, a D2-dopamine agonist (Cycloset) on vascular function in patients with type 2 diabetes (T2D). STUDY DESIGN AND METHODS Fifteen poorly controlled T2D treated with metformin plus glucagon-like peptide-1 receptor agonists (GLP-1RA) were studied after 4 months of Cycloset, 3.2 mg/d. Subjects received a 5-hour double-tracer (iv 3-3H-glucose and oral 14C-glucose) mixed meal test (MMT) to quantitate rates of endogenous glucose production (EGP), oral glucose appearance (RaO) and disappearance (Rd) pre- and post-Cycloset. Vascular assessments included 2-day continuous BP monitoring, reactive hyperaemia index (RHI) and arterial stiffness (AS). RESULTS HbA1c decreased from 8.3 ± 0.3% to 7.7 ± 0.2% (P < 0.05), fasting plasma glucose did not change (143 ± 4 vs 147 ± 5) and mean plasma glucose during MTT decreased from 223 ± 3 to 210 ± 4 mg/dL (P < 0.05) after Cycloset. Basal EGP (2.2 ± 0.2 vs 2.1 ± 0.2 mg/kg min) was unchanged, but there was greater MMT suppression (1.1 ± 0.1 vs 0.7 ± 0.1, P < 0.05). After Cycloset, RaO declined from 2.0 ± 0.1 to 1.7 ± 0.2 mg/kg min and peripheral oral glucose appearance from 53.1 ± 3.2 to 44.4 ± 3.1 g (P < 0.01). There were no changes in plasma insulin or glucagon concentration. Systolic (134 ± 4 vs 126 ± 6), diastolic (78 ± 3 vs 73 ± 4), mean BP (97 ± 5 vs 90 ± 4) and pulse pressure (54 ± 2 vs 51 ± 2 mm Hg) were reduced; RHI increased from 1.4 ± 0.1 to 1.9 ± 0.3 au and AS decreased modestly (19.8 ± 4.1 to 16.2 ± 3.7 au, P = NS). CONCLUSIONS Addition of Cycloset to GLP-1 RA improved vascular indices and postprandial hyperglycaemia in T2DM primarily by lowering oral glucose appearance, suggesting that hepatic glucose uptake was enhanced. Improved vascular indices may explain the reduction in cardiovascular events observed with Cycloset therapy in patients with T2DM.
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Affiliation(s)
- Mariam Alatrach
- Texas Diabetes InstituteUniversity Health SystemSan AntonioTexas
- Division of DiabetesDepartment of MedicineUniversity of Texas Health Science Center at San AntonioSan AntonioTexas
| | - Christina Agyin
- Texas Diabetes InstituteUniversity Health SystemSan AntonioTexas
- Division of DiabetesDepartment of MedicineUniversity of Texas Health Science Center at San AntonioSan AntonioTexas
| | - John Adams
- Texas Diabetes InstituteUniversity Health SystemSan AntonioTexas
- Division of DiabetesDepartment of MedicineUniversity of Texas Health Science Center at San AntonioSan AntonioTexas
| | - Robert Chilton
- Texas Diabetes InstituteUniversity Health SystemSan AntonioTexas
- Division of DiabetesDepartment of MedicineUniversity of Texas Health Science Center at San AntonioSan AntonioTexas
| | - Curtis Triplitt
- Texas Diabetes InstituteUniversity Health SystemSan AntonioTexas
- Division of DiabetesDepartment of MedicineUniversity of Texas Health Science Center at San AntonioSan AntonioTexas
| | - Ralph A. DeFronzo
- Texas Diabetes InstituteUniversity Health SystemSan AntonioTexas
- Division of DiabetesDepartment of MedicineUniversity of Texas Health Science Center at San AntonioSan AntonioTexas
| | - Eugenio Cersosimo
- Texas Diabetes InstituteUniversity Health SystemSan AntonioTexas
- Division of DiabetesDepartment of MedicineUniversity of Texas Health Science Center at San AntonioSan AntonioTexas
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Schwetz V, Librizzi R, Trummer C, Theiler G, Stiegler C, Pieber TR, Obermayer-Pietsch B, Pilz S. Treatment of hyperprolactinaemia reduces total cholesterol and LDL in patients with prolactinomas. Metab Brain Dis 2017; 32:155-161. [PMID: 27525431 PMCID: PMC5566581 DOI: 10.1007/s11011-016-9882-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 07/25/2016] [Indexed: 11/17/2022]
Abstract
Previous studies suggest that hyperprolactinaemia might have adverse effects on lipid and glucose metabolism. We therefore aimed to evaluate whether dopamine agonist treatment with cabergoline has significant effects on blood lipids, fasting glucose and HbA1c levels in patients with micro- or macroprolactinoma. In this retrospective observational study the main outcome measures are changes in parameters of glucose and lipid metabolism compared at hyperprolactinaemia and after achievement of normoprolactinaemia by cabergoline treatment. We enrolled 53 study participants (22 females; median [interquartile range] age: 40.0 [27.5 to 50.0] years), 22 (41.5 %) with micro-, and 31 (58.5 %) with macroprolactinomas. After a median follow-up of 9 months, prolactin levels decreased from 220.6 (80.7-913.4) to 11.2 (3.5-18.7) ng/mL (p < 0.001). There was a significant decrease in median levels of low-density lipoprotein (LDL) from 121.6 (±39.4) to 110.6 mg/dl (±37.6, p = 0.005) and total cholesterol from 191 (168.5-241) to 181 mg/dl (162-217, p < 0.001), but no change in high-density lipoprotein (HDL), triglycerides, fasting glucose and HbA1c. We observed a significant increase in testosterone in men and in oestradiol in women. In linear regression analyses using the change in total cholesterol or LDL as dependent, and the change in prolactin, oestradiol, and testosterone as independent variables, no significant predictor of the change in total cholesterol or LDL was identified. In patients with prolactinomas, normalisation of elevated prolactin levels by cabergoline treatment was accompanied by significant reductions in LDL and total cholesterol. Further studies are warranted to confirm our findings and to evaluate the clinical implications of lipid levels in the monitoring and treatment of patients with prolactinomas.
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Affiliation(s)
- Verena Schwetz
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria.
| | - Rosaria Librizzi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria
| | - Christian Trummer
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria
| | - Georg Theiler
- Department of Internal Medicine, Feldbach Regional Hospital, Feldbach, Austria
| | - Claudia Stiegler
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria
| | - Thomas R Pieber
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria
| | - Barbara Obermayer-Pietsch
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria
| | - Stefan Pilz
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria
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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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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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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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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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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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Grunberger G. Novel therapies for the management of type 2 diabetes mellitus: part 1. pramlintide and bromocriptine-QR. J Diabetes 2013; 5:110-7. [PMID: 23452312 DOI: 10.1111/1753-0407.12034] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 02/02/2013] [Accepted: 02/12/2013] [Indexed: 11/28/2022] Open
Abstract
Several classes of antidiabetic agents have been introduced into the market place over the past dozen years. As our understanding of the underlying pathophysiology of type 2 diabetes has advanced, attempts have been made to address these defects specifically. This brief review focuses on our experience with two such pharmacological approaches: (i) a synthetic amylin analog addressing amylin deficiency; and (ii) a dopaminergic agonist, focused on enhancing the lowered dopaminergic tone in patients with type 2 diabetes. Importantly, the use of these agents is not associated with hypoglycemia or weight gain.
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Ooi CP, Loke SC. Bromocriptine for type 2 diabetes mellitus. Hippokratia 2013. [DOI: 10.1002/14651858.cd010319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Cheow Peng Ooi
- Faculty of Medicine and Health Sciences, Universiti Putra Malaysia; Endocrine Unit, Department of Medicine; Serdang Selangor DE Malaysia 43400
| | - Seng Cheong Loke
- Universiti Putra Malaysia; Institute of Gerontology; Serdang Selangor DE Malaysia 43400
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Thulé PM. Mechanisms of current therapies for diabetes mellitus type 2. ADVANCES IN PHYSIOLOGY EDUCATION 2012; 36:275-83. [PMID: 23209008 PMCID: PMC3776431 DOI: 10.1152/advan.00094.2012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 09/21/2012] [Indexed: 06/12/2023]
Abstract
The array of medications available for the treatment of hyperglycemia has increased rapidly in the previous decade, and recent investigations have clarified novel mechanisms underlying the antihyperglycemic efficacy of these drugs. This article reviews the mechanisms of action for medications currently approved to treat diabetes mellitus in the United States, with the exception of insulin and its analogs. Finally, it attempts to integrate these mechanisms into the schema of pathophysiological factors that combine to produce hyperglycemia in patients with diabetes mellitus.
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Affiliation(s)
- Peter M Thulé
- Emory University School of Medicine, Decatur, Georgia, USA.
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Abstract
A quick-release formulation of bromocriptine is the latest drug approved by the US Food and Drug Administration for the treatment of type 2 diabetes mellitus. Most interestingly, the development of this drug stems from studies of hibernation in rodents. This article will review the physiology that led to the development of this new drug, as well as its indications, clinical use, benefits, and contraindications.
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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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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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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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de Leeuw van Weenen JE, Parlevliet ET, Maechler P, Havekes LM, Romijn JA, Ouwens DM, Pijl H, Guigas B. The dopamine receptor D2 agonist bromocriptine inhibits glucose-stimulated insulin secretion by direct activation of the alpha2-adrenergic receptors in beta cells. Biochem Pharmacol 2010; 79:1827-36. [PMID: 20138024 DOI: 10.1016/j.bcp.2010.01.029] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Revised: 01/22/2010] [Accepted: 01/25/2010] [Indexed: 01/30/2023]
Abstract
Treatment with the dopamine receptor D2 (DRD2) agonist bromocriptine improves metabolic features in obese patients with type 2 diabetes by a still unknown mechanism. In the present study, we investigated the acute effect of bromocriptine and its underlying mechanism(s) on insulin secretion both in vivo and in vitro. For this purpose, C57Bl6/J mice were subjected to an intraperitoneal glucose tolerance test (ipGTT) and a hyperglycemic (HG) clamp 60min after a single injection of bromocriptine or placebo. The effects of bromocriptine on glucose-stimulated insulin secretion (GSIS), cell membrane potential and intracellular cAMP levels were also determined in INS-1E beta cells. We report here that bromocriptine increased glucose levels during ipGTT in vivo, an effect associated with a dose-dependent decrease in GSIS. During the HG clamp, bromocriptine reduced both first-phase and second-phase insulin response. This inhibitory effect was also observed in INS-1E beta cells, in which therapeutic concentrations of bromocriptine (0.5-50nM) decreased GSIS. Mechanistically, neither cellular energy state nor cell membrane depolarization was affected by bromocriptine whereas intracellular cAMP levels were significantly reduced, suggesting involvement of G-protein-coupled receptors. Surprisingly, the DRD2 antagonist domperidone did not counteract the effect of bromocriptine on GSIS, whereas yohimbine, an antagonist of the alpha2-adrenergic receptors, completely abolished bromocriptine-induced inhibition of GSIS. In conclusion, acute administration of bromocriptine inhibits GSIS by a DRD2-independent mechanism involving direct activation of the pancreatic alpha2-adrenergic receptors. We suggest that treatment with bromocriptine promotes beta cells rest, thereby preventing long-lasting hypersecretion of insulin and subsequent beta cell failure.
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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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Kok P, Roelfsema F, Frölich M, van Pelt J, Meinders AE, Pijl H. Short-term treatment with bromocriptine improves impaired circadian growth hormone secretion in obese premenopausal women. J Clin Endocrinol Metab 2008; 93:3455-61. [PMID: 18559918 DOI: 10.1210/jc.2008-0001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT A profound reduction of spontaneous as well as stimulated GH secretion has been consistently observed in obesity. Dopamine promotes GH release through activation of dopamine D2 receptors (D2Rs). Dopamine D2R availability in the brain is reduced in obese humans in proportion to body adiposity. We hypothesized that impaired dopamine D2R signaling is mechanistically involved in the deficient GH secretion associated with obesity. OBJECTIVE To test this hypothesis, we studied the effect of short-term bromocriptine (B) (a D2R agonist) treatment on spontaneous 24-h GH secretion in obese women, while body weight and caloric intake remained constant. DESIGN This was a prospective, fixed order, cross-over study. SETTING The study was performed in the Clinical Research Center at Leiden University Medical Center. PARTICIPANTS There were 18 healthy obese women (body mass index 33.2 +/- 0.6 kg/m2) studied twice in the early follicular phase of their menstrual cycle. INTERVENTION(S) Eight days of treatment with B and placebo (Pl) was performed. MAIN OUTCOME MEASURE(S) Blood was collected during 24 h at 10-min intervals for determination of GH concentrations. GH secretion parameters were calculated using deconvolution analysis. RESULTS Short-term treatment with B significantly enhanced diurnal GH secretion (Pl 121.4 +/- 16.4 vs. B 155.4 +/- 15.2 microg/liter(volume of distribution).24 h; P = 0.01), whereas IGF-I concentrations remained constant (Pl 22.4 +/- 2.4 vs. B 21.8 +/- 1.6 nmol/liter; P = 0.928). CONCLUSIONS Activation of dopamine D2Rs by B favorably affects impaired nyctohemeral GH secretion in obese women. Reduced dopaminergic neuronal signaling might be involved in the pathogenesis of obesity associated hyposomatotropism.
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Affiliation(s)
- Petra Kok
- Department of General Internal Medicine, Leiden University Medical Center, RC Leiden, The Netherlands
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Naliato ECDO, Violante AHD, Caldas D, Farias MLF, Bussade I, Lamounier Filho A, Loureiro CR, Fontes R, Schrank Y, Loures T, Colao A. Bone density in women with prolactinoma treated with dopamine agonists. Pituitary 2008; 11:21-8. [PMID: 17661178 DOI: 10.1007/s11102-007-0064-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES (1) to evaluate bone density in women with prolactinoma treated with dopamine agonists and healthy controls, using dual energy x-ray absorptiometry (DXA), (2) to classify the results according to the current International Society for Clinical Densitometry (ISCD) criteria, and (3) to correlate bone density with lean and fat masses, biochemical data and clinical aspects of prolactinomas. MATERIALS AND METHODS A cross-sectional study was performed in two University referral centers. Forty-five premenopausal women with prolactinoma were submitted to DXA and blood analysis (prolactin, estradiol, testosterone, SHBG, calcium, phosphorus, PTH, C-telopeptides of type 1 collagen, and osteocalcin) by the time of their clinical evaluation. They were compared with 25 control women of similar age and body mass index distribution. RESULTS Women with prolactinoma had lower lumbar spine Z-score than controls. Femoral neck, trochanter, and total proximal femur Z-scores were similar in patients and controls. Twenty-two percent of the patients had Z-scores below the expected age range vs. 4% in the control group. Lumbar spine, femoral neck, and total proximal femur Z-scores were mainly correlated with the amenorrhea duration. The trochanter Z-score was associated with the gynoid lean/fat mass ratio. CONCLUSIONS Based on the current ISCD criteria, bone density evaluation in women with prolactinoma reveals bone loss, especially of trabecular type. Bone density in these patients was particularly associated with the duration of amenorrhea, which reinforces the importance of the adequate disease control in women with prolactinoma in order to avoid complications of this disease.
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Naliato ECO, Violante AHD, Caldas D, Lamounier Filho A, Loureiro CR, Fontes R, Schrank Y, Souza RG, Costa PLM, Colao A. Body fat in nonobese women with prolactinoma treated with dopamine agonists. Clin Endocrinol (Oxf) 2007; 67:845-52. [PMID: 17645576 DOI: 10.1111/j.1365-2265.2007.02973.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To evaluate body fat in nonobese women with prolactinoma treated with dopamine agonists, using whole body dual energy X-ray absorptiometry (DXA) and to correlate DXA results with biochemical data and clinical aspects of the prolactinoma. DESIGN, PATIENTS AND MEASUREMENTS A cross-sectional study was performed in two University referral centres. Thirty-one nonobese premenopausal women with prolactinoma were subjected to DXA and blood analysis at clinical evaluation. They were compared with 21 control women of similar age and body mass index (BMI). RESULTS Women with prolactinoma treated with dopamine agonists and controls had similar body fat percentages in all sites evaluated with DXA (arms, legs, trunk, android, gynoid and total body). Patients with normal PRL levels at study entry had lower body fat percentages in all sites. In the patient group, arm, leg, truncal, android, gynoid and total body fat were positively associated with PRL levels. CONCLUSION Body fat percentage is similar in nonobese women with prolactinoma and in controls. The lower body fat content in patients with normal PRL levels is likely to be due to the metabolic effects of adequate dopamine receptor type 2 (DR2) activation as a result of regular dopamine agonist treatment. This finding reinforces the importance of the appropriate treatment with dopamine agonists in women with prolactinoma, which, besides normalizing PRL levels, reduces body fat content and the consequent risk of developing Metabolic Syndrome and its complications.
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Affiliation(s)
- Erika C O Naliato
- Division of Endocrinology, Department of Internal Medicine, Federal University of Rio de Janeiro, Hyperprolactinemia Unit, Clementino Fraga Filho University Hospital, Rio de Janeiro, Brazil.
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Kok P, Roelfsema F, Frölich M, van Pelt J, Stokkel MPM, Meinders AE, Pijl H. Activation of dopamine D2 receptors simultaneously ameliorates various metabolic features of obese women. Am J Physiol Endocrinol Metab 2006; 291:E1038-43. [PMID: 16803851 DOI: 10.1152/ajpendo.00567.2005] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The metabolic syndrome comprises a cluster of metabolic anomalies including insulin resistance, abdominal obesity, dyslipidemia, and hypertension. Previous studies suggest that impaired dopamine D2 receptor (D2R) signaling is involved in its pathogenesis. We studied the acute effects of bromocriptine (a D2R agonist) on energy metabolism in obese women; body weight and caloric intake remained constant. Eighteen healthy, obese women (BMI 33.2 +/- 0.6 kg/m(2), mean age 37.5 +/- 1.7, range 22-51 yr) were studied twice in the follicular phase of their menstrual cycle in a prospective, single-blind, crossover design. Subjects received both placebo (P; always first occasion) and bromocriptine (B; always second occasion) on separate occasions for 8 days. At each occasion blood glucose and insulin were assessed every 10 min for 24 h, and circadian plasma free fatty acid (FFA) and triglyceride (TG) levels were measured hourly. Fuel oxidation was determined by indirect calorimetry. Body weight and composition were not affected by the drug. Mean 24-h blood glucose (P < 0.01) and insulin (P < 0.01) were significantly reduced by bromocriptine, whereas mean 24 h FFA levels were increased (P < 0.01), suggesting that lipolysis was stimulated. Bromocriptine increased oxygen consumption (P = 0.03) and resting energy expenditure (by 50 kcal/day, P = 0.03). Systolic blood pressure was significantly reduced by bromocriptine. Thus these results imply that short-term bromocriptine treatment ameliorates various components of the metabolic syndrome while it shifts energy balance away from lipogenesis in obese humans.
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Affiliation(s)
- Petra Kok
- Department of General Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands
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Kuo DY. Hypothalamic neuropeptide Y (NPY) and the attenuation of hyperphagia in streptozotocin diabetic rats treated with dopamine D1/D2 agonists. Br J Pharmacol 2006; 148:640-7. [PMID: 16702993 PMCID: PMC1751870 DOI: 10.1038/sj.bjp.0706754] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Accepted: 03/17/2006] [Indexed: 11/08/2022] Open
Abstract
1. Dopamine is an appetite suppressant, while neuropeptide Y (NPY), an appetite stimulant in the brain, is reported to be involved in anorectic action induced by a combined administration of D1/D2 agonists in normal rats. In diabetic rats, however, these factors have not been studied. 2. Rats (including normal, diabetic and insulin-treated diabetic rats) were given daily injections of saline or D1/D2 agonists for 6 days. Changes in food intake and hypothalamic NPY content of these rats were assessed and compared. 3. The D1/D2 agonist-induced anorectic responses were altered in diabetic rats compared to normal rats treated similarly. Both the anorectic response on the first day of dosing and the tolerant response on the subsequent days were attenuated. 4. This alteration was independent of the neuroendocrine disturbance on feeding behavior since the basic pattern of food intake during the time course of a 24-h day/night cycle was similar in normal and diabetic rats; the decrease of food intake following drug treatment was only shown at the initial interval of 0-6 h in both groups of rats. 5. However, this alteration coincided with changes in NPY content following D1/D2 coadministration. The replacement of insulin in diabetic rats could normalize both NPY content and D1/D2 agonist-induced anorexia. 6. It is demonstrated that the response of D1/D2 agonist-induced appetite suppression is attenuated in diabetic rats compared to normal rats and that elevated hypothalamic NPY content may contribute to this alteration.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/administration & dosage
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/therapeutic use
- Animals
- Appetite Depressants/therapeutic use
- Diabetes Mellitus, Experimental/drug therapy
- Dopamine Agonists/administration & dosage
- Dopamine Agonists/therapeutic use
- Drug Administration Routes
- Drug Therapy, Combination
- Eating/drug effects
- Feeding Behavior/drug effects
- Hormone Replacement Therapy
- Hyperphagia/drug therapy
- Hypothalamus/physiology
- Injections
- Insulin/therapeutic use
- Male
- Neuropeptide Y/metabolism
- Neuropeptide Y/physiology
- Quinpirole/administration & dosage
- Quinpirole/therapeutic use
- Rats
- Rats, Wistar
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D2/agonists
- Time Factors
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Affiliation(s)
- Dong-Yih Kuo
- Department of Physiology, Chung Shan Medical University, Taichung City, Taiwan 40201, ROC.
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Aminorroaya A, Janghorbani M, Ramezani M, Haghighi S, Amini M. Does Bromocriptine Improve Glycemic Control of Obese Type-2 Diabetics? Horm Res Paediatr 2004; 62:55-9. [PMID: 15205563 DOI: 10.1159/000078932] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2003] [Accepted: 04/20/2004] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Various oral hypoglycemic agents have already been administered to type-2 diabetic patients to normalize their plasma glucose concentrations but they have not had complete and sustained success. In recent years, bromocriptine has been tried with controversial results. In present study, the effect of bromocriptine on glycemic control was evaluated in obese type-2 diabetic patients. METHODS In a double-blind placebo-controlled clinical trial, 40 obese patients with type-2 diabetes (aged 32-70 years) were randomly allocated to the two treatment groups. The first group received bromocriptine (2.5 mg daily) for a total of 3 months. The second group received placebo. They had been uncontrolled on fixed doses of glibenclamide or its combination with metformin in the 3 months before enrolling in the study. The fasting plasma glucose (FPG) level and glycosylated hemoglobin (HbA1) were measured and body mass index (BMI) was calculated before and 1, 2 and 3 months after treatment. RESULTS The FPG level decreased in the bromocriptine-treated group from 10.59 +/- 0.42 to 9.06 +/- 0.41 mmol/l (mean +/- SEM; p < 0.01), whereas in the placebo group it was not changed, 10.69 +/- 0.52 and 10.6 +/- 0.57 mmol/l, respectively. The HbA1 concentration was reduced in the bromocriptine-treated group from 9.9 +/- 0.3 to 9.5 +/-0.2% (p = 0.06), whereas it increased in the placebo-treated group from 10.2 +/- 0.3 to 11.3 +/- 0.6% (p < 0.05). The differences in HbA1 (1.8%, p < 0.01) and FPG (1.55 mmol/l, p < 0.05) levels between the bromocriptine and placebo groups at 3 months were significant. No changes in body weight or BMI occurred during the study in either placebo- or bromocriptine-treated group. CONCLUSION The data further support the contention that bromocriptine improves glycemic control in obese type-2 diabetic patients, although the mechanism of action remains to be determined.
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Affiliation(s)
- Ashraf Aminorroaya
- Isfahan Endocrinology and Metabolism Research Center, Isfahan University of Medical Sciences and Health Services, Isfahan, Iran.
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Pijl H. Reduced dopaminergic tone in hypothalamic neural circuits: expression of a "thrifty" genotype underlying the metabolic syndrome? Eur J Pharmacol 2004; 480:125-31. [PMID: 14623356 DOI: 10.1016/j.ejphar.2003.08.100] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The thrifty genotype hypothesis postulates that the genetically determined ability to grow obese and insulin resistant in times of food abundance confers a survival advantage in times of famine. Obviously, this ability poses a major health threat in modern times, where food is always available in large quantities. In the last 10-15 years, many genes encoding pathways that orchestrate energy balance and fuel flux have been discovered. This paper summarizes the evidence that diminished dopaminergic tone in hypothalamic nuclei contributes to the "thrifty" genotype/phenotype. Reduced dopaminergic neurotransmission in the suprachiasmatic nucleus of seasonally obese animals appears to drive noradrenalin and NPY mediated transmissions in other nuclei to induce the obesity syndrome at the appropriate time of year. Treatment with dopamine D(2) receptor agonists can fully reverse the metabolic syndrome in these animals. Similar mechanisms are operative in non-seasonal obese animal models. In man, treatment with dopamine D(2) receptor antagonists induces obesity and type 2 diabetes mellitus, whereas dopamine D(2) receptor activation ameliorates the metabolic profile in obese nondiabetic and diabetic humans. Various loss of function mutations of the dopamine D(2) receptor gene are associated with overweight in humans. In concert, the data support the notion that diminution of dopaminergic (dopamine D(2) receptor mediated) transmission in relevant hypothalamic nuclei sets the stage for efficient partitioning of ingested nutrients to contribute to a phenotype that is not so thrifty anymore.
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Affiliation(s)
- Hanno Pijl
- Department of Internal Medicine, Leiden University Medical Center, C1-R39, PO Box 9600, 2300 RC, Leiden, The Netherlands.
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Umrani DN, Goyal RK. Fenoldopam treatment improves peripheral insulin sensitivity and renal function in STZ-induced type 2 diabetic rats. Clin Exp Hypertens 2003; 25:221-33. [PMID: 12797596 DOI: 10.1081/ceh-120020392] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Dopamine and diabetes mellitus are reported to have close link between them. We have studied the effect of six-week treatment with D1 receptor agonist fenoldopam (1 mg/kg, i.p., daily) on glucose, lipid, and renal profile in streptozotocin (STZ)-induced (non-insulin dependent) type 2 diabetic rats. Streptozotocin (90 mg/kg, i.p.) was injected to two day old Sprague-Dawley pups. Streptozotocin produced hyperglycemia, hyperinsulinemia, hyperlipidemia, hypertension, increase in serum urea and creatinine by the time animals were 10 week old. Treatment with fenoldopam significantly decreased serum glucose, insulin, cholesterol, triglyceride, urea, creatinine, and blood pressure. During oral glucose tolerance test (OGTT), diabetic rats showed increase in AUC(glucose) and AUC(insulin). Fenoldopam significantly decreased AUC(glucose) in diabetic rats. Diabetic rats showed lower insulin sensitivity index (K(TTT)) that was significantly increased by treatment with fenoldopam in diabetic rats. Diabetic rats showed decrease in urinary sodium. Fenoldopam treatment significantly increased urine output as well as urinary sodium indicating reduced sodium retention. Our data indicates fenoldopam treatment improves peripheral insulin sensitivity and renal function in STZ-induced type 2 diabetic rats.
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Zorad S, Golda V, Fickova M, Macho L, Pinterova L, Jurcovicova J. Terguride treatment attenuated prolactin release and enhanced insulin receptor affinity and GLUT 4 content in obese spontaneously hypertensive female, but not male rats. Ann N Y Acad Sci 2002; 967:490-9. [PMID: 12079879 DOI: 10.1111/j.1749-6632.2002.tb04307.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Glucose tolerance, serum insulin, insulin receptors in epididymal fat tissue, and GLUT 4 content in muscle, as well as serum prolactin, were studied in obese and lean spontaneously hypertensive rats (SHRs) of both sexes. Obese animals displayed insulin resistance and decreased capacity of high-affinity binding sites of insulin receptors in fat tissue plasma membranes. GLUT 4 content in musculus quadriceps was diminished only in obese females. Terguride treatment lowered prolactin serum levels, which was concomitant with ameliorated insulin sensitivity in obese animals of both sexes. Similarly, only in obese females, terguride significantly increased the affinity of high-affinity insulin-binding sites and normalized GLUT 4 content. Our results document downregulation of insulin receptors and GLUT 4 in obesity and suggest a role for prolactin in obesity-induced insulin resistance, particularly in female rats.
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Affiliation(s)
- S Zorad
- Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
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Bartness TJ, Demas GE, Song CK. Seasonal changes in adiposity: the roles of the photoperiod, melatonin and other hormones, and sympathetic nervous system. Exp Biol Med (Maywood) 2002; 227:363-76. [PMID: 12037125 DOI: 10.1177/153537020222700601] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
It appears advantageous for many non-human animals to store energy body fat extensively and efficiently because their food supply is more labile and less abundant than in their human counterparts. The level of adiposity in many of these species often shows predictable increases and decreases with changes in the season. These cyclic changes in seasonal adiposity in some species are triggered by changes in the photoperiod that are faithfully transduced into a biochemical signal through the nightly secretion of melatonin (MEL) via the pineal gland. Here, we focus primarily on the findings from the most commonly studied species showing seasonal changes in adiposity-Siberian and Syrian hamsters. The data to date are not compelling for a direct effect of MEL on white adipose tissue (WAT) and brown adipose tissue (BAT) despite some recent data to the contrary. Thus far, none of the possible hormonal intermediaries for the effects of MEL on seasonal adiposity appear likely as a mechanism by which MEL affects the photoperiodic control of body fat levels indirectly. We also provide evidence pointing toward the sympathetic nervous system as a likely mediator of the effects of MEL on short day-induced body fat decreases in Siberian hamsters through increases in sympathetic drive on WAT and BAT. We speculate that decreases in the SNS drive to these tissues may underlie the photoperiod-induced seasonal increases in body fat of species such as Syrian hamsters. Clearly, we need to deepen our understanding of seasonal adiposity, although, to our knowledge, this is the only form of environmentally induced changes in body fat where the key elements of its external trigger have been identified and can be traced to and through their transduction into a physiological stimulus that ultimately affects identified responses of white adipocyte physiology and cellularity. Finally, the comparative physiological approach to the study of seasonal adiposity seems likely to continue to yield significant insights into the mechanisms underlying this phenomenon and for understanding obesity and its reversal in general.
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Affiliation(s)
- Timothy J Bartness
- Department of Biology and of Psychology, Neurobiology and Behavior Program, Georgia State University, Atlanta, Georgia 30303, USA.
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Abstract
A plethora of data from experimental animals provide strong support for the concept that reduced dopaminergic neuronal activity and enhanced noradrenergic tone in specific hypothalamic nuclei are involved in the pathogenesis of the metabolic syndrome. The available information on these neurotransmitter systems in insulin-resistant humans with obesity is in keeping with the postulate that analogous mechanisms may underlie their adverse metabolic profile. Treatment with bromocriptine, which has dopaminergic (D2 receptor agonist) and sympatholytic (alpha2-adrenoceptor agonistic and an alpha1-adrenoceptor antagonistic) actions, can reverse the metabolic anomalies in a variety of obese mammalian species. Combined D1/D2 receptor activation appears to exert even more powerful effects on fuel metabolism in various animal models of the metabolic syndrome. The currently available data on the metabolic effects of bromocriptine in humans with obesity and type 2 diabetes mellitus point in the same direction. Bromocriptine favorably affects glucose metabolism and various other components of the metabolic syndrome simultaneously to ameliorate the risk of damage to eyes, neural tissue, kidneys and the cardiovascular system in patients with type 2 diabetes mellitus. Moreover, a substantial number of studies indicate that bromocriptine lowers blood pressure in animals and humans with hypertension via its sympatholytic capacities. However, the effects of bromocriptine alone are relatively modest, the metabolic mechanism of action in humans remains uncertain, and the long-term efficacy and safety profiles of this compound are unknown. It seems important to seek for ways to boost the action of bromocriptine, by combining dopaminergic D2 and D1 receptor activation, for example. Notably, there is no antidiabetic drug that acts through central (dopaminergic) mechanisms. This novel approach may, therefore, result in synergistic actions with other available agents to favorably impact the risk of tissue damage in patients with type 2 diabetes mellitus.
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Affiliation(s)
- Hanno Pijl
- Leiden University Medical Center, Department of Internal Medicine, Leiden, The Netherlands.
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40
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Mauer MM, Harris RB, Bartness TJ. The regulation of total body fat: lessons learned from lipectomy studies. Neurosci Biobehav Rev 2001; 25:15-28. [PMID: 11166075 DOI: 10.1016/s0149-7634(00)00047-6] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Surgical removal of body fat (partial lipectomy) is a means of directly reducing fat such that metabolic and behavioral responses can be readily attributed to the lipid deficit. If total body fat is regulated, then lipectomy should trigger compensatory increases in nonexcised white adipose tissue (WAT) mass and/or regrowth at excision sites. Many species, including laboratory rats and mice, show lipectomy-induced compensatory recovery of body fat. Those animals exhibiting naturally occurring annual adiposity cycles, such as ground squirrels and hamsters, do so most impressively reaching seasonally appropriate body fat levels indistinguishable from controls. Reparation of the lipid deficit occurs without an increase in food intake, and generally through enlargement of non-excised WAT mass, rather than regrowth of excised WAT. A body fat regulatory system involving humoral and sensory neural inputs to the brain as well as sympathetic neural outputs from brain to adipose tissue is presented. Collectively, the lipectomy model appears useful for testing mechanisms controlling adiposity, or individual depot growth, and offers insight into how lipid stores fluctuate naturally.
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Affiliation(s)
- M M Mauer
- Department of Biology and the Neurobiology and Behavior Program, Georgia State University, University Plaza, Atlanta, GA 30303-3083, USA
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Cincotta AH, Meier AH, Cincotta M. Bromocriptine improves glycaemic control and serum lipid profile in obese Type 2 diabetic subjects: a new approach in the treatment of diabetes. Expert Opin Investig Drugs 1999; 8:1683-1707. [PMID: 11139820 DOI: 10.1517/13543784.8.10.1683] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Bromocriptine, a potent dopamine D(2) receptor agonist, has been shown to reduce insulin resistance, glucose intolerance and hyperlipidaemia in both numerous animal studies and in Phase II studies. Bromocriptine has been used worldwide for over 20 years to treat Parkinson's disease, macroprolactinoma and other disorders; it has been found to be generally safe. We therefore investigated the possible beneficial effects of Ergoset(R) (Ergo Science Corp.), a new quick release formulation of bromocriptine, on glycaemic control and serum lipid profile in obese Type 2 diabetic subjects in two large Phase III studies. A large, randomised, double-blind placebo-controlled study was conducted in which Ergoset was given once daily at 8 am. (4.8 mg maximum dose) for 24 weeks as adjunctive therapy to sulphonylurea (485 subjects) to obese Type 2 diabetics held on a weight- maintaining diet. Treatment efficacy parameters included change from baseline in glycated haemoglobin A(1c) (HbA(1c)), fasting and post-prandial serum glucose, insulin, triglyceride and free fatty acid levels. Baseline glycated haemoglobin, fasting glucose, insulin, triglyceride and free fatty acid levels did not differ between treatment groups. and on average were 9.4 +/- 0.05%, 222 +/- 2 mg/dl, 24 +/- 1 µU/ml, 248 +/- 11 mg/dl, and 850 +/- 32 µEq/l, respectively. A similarly designed study of Ergoset as monotherapy in Type 2 diabetics (154 subjects) with similar baseline clinical characteristics was conducted. Addition of Ergoset treatment to sulphonylurea reduced percent glycated HbA(1c) by 0.55 (P < 0.0001) (approximately 1.0 for responders, 65% of population), fasting and post-prandial glucose by 23 and 26 mg/dl (P < 0.0002), fasting and post-prandial triglycerides by 72 and 63 mg/dl (P < 0.005) and fasting and post-prandial free fatty acids by 150 and 165 µEq/l (P < 0.05), relative to placebo. Twelve percent of all Ergoset subjects, compared to 3% of placebo subjects, withdrew from the study due to adverse events. The most common events causing withdrawal were nausea, dizziness, asthenia, and rhinitis (representing 4.5, 3.3, 2.0, and 0.8% of the total Ergoset populations, respectively). The incidence of serious adverse events did not differ between Ergoset- (3.4%) and placebo- (4.3%) treated subjects. Ergoset as monotherapy also improved glycaemic control (0.56 HbA(1c) decrease relative to placebo after 24 weeks of treatment; P < 0.02). Once daily Ergoset treatment improves glycaemic control and serum lipid profile and is well-tolerated in obese Type 2 diabetics.
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Affiliation(s)
- A H Cincotta
- Ergo Science Corp., North Andover Mills, 43 High Street, North Andover, MA 01845, USA.
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42
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Zhang Y, Scislowski PW, Prevelige R, Phaneuf S, Cincotta AH. Bromocriptine/SKF38393 treatment ameliorates dyslipidemia in ob/ob mice. Metabolism 1999; 48:1033-40. [PMID: 10459570 DOI: 10.1016/s0026-0495(99)90202-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Our previous studies have shown that the dopaminergic D1 receptor agonist SKF38393 (SKF) plus the D2 receptor agonist bromocriptine (BC) act synergistically to reduce obesity in obese C57BL/6J (ob/ob) mice. The present study investigated the effects of this combination on dyslipidemia in ob/ob mice. Female ob/ob mice were treated daily with vehicle or SKF (20 mg/kg body weight [BW]) plus BC (16 mg/kg BW [BC/SKF]) for 14 days. The animals were then used for the characterization of plasma lipoprotein profiles, hepatic triacylglycerol synthesis and secretion, adipocyte lipolysis, adipose and muscle lipoprotein lipase (LPL) activity, and muscle triglyceride (TG) content. The treatment significantly reduced plasma glucose 54%, TG 41%, cholesterol 21%, phospholipid 20%, and free fatty acid (FFA) 36% (P < .01). Hepatic triacylglycerol synthesis was 55% lower in treated mice versus control mice (P < .01). The cell size of isolated adipocytes was significantly reduced (41%) by treatment. LPL activity was increased in soleus skeletal muscle (25%, P < .05) but was sharply reduced in adipose tissue (91%, P < .01) in treated versus control mice. The TG content of hindlimb muscle was about 49% lower in treated versus control mice (P < .05). The basal and isoproterenol-stimulated lipolytic rate was decreased (approximately 53%) in adipocytes from treated animals compared with the control (P < .01). In conclusion, BC/SKF normalized the hypertriglyceridemia likely via its simultaneous antilipogenic action in liver tissue and antilipolytic action in adipose tissue. Decreased plasma flux of FFA partially contributed to the reduced hepatic lipogenesis, plasma very-low-density lipoprotein (VLDL)-TG, and TG in skeletal muscle. The above-described effects of BC/SKF treatment are largely independent of its effect to normalize hyperphagia in ob/ob mice.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/therapeutic use
- Adipose Tissue/metabolism
- Animals
- Bromocriptine/pharmacology
- Bromocriptine/therapeutic use
- Dopamine Agonists/pharmacology
- Dopamine Agonists/therapeutic use
- Drug Synergism
- Drug Therapy, Combination
- Female
- Hyperlipidemias/drug therapy
- Hyperlipidemias/metabolism
- Lipolysis/drug effects
- Lipoproteins/blood
- Mice
- Mice, Obese
- Receptors, Dopamine/metabolism
- Triglycerides/metabolism
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Affiliation(s)
- Y Zhang
- ErgoScience Corp, Charlestown, MA 02129, USA
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Luo S, Liang Y, Cincotta AH. Intracerebroventricular administration of bromocriptine ameliorates the insulin-resistant/glucose-intolerant state in hamsters. Neuroendocrinology 1999; 69:160-6. [PMID: 10087448 DOI: 10.1159/000054415] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Bromocriptine, a potent dopamine D2 receptor agonist, suppresses lipogenesis and improves glucose intolerance and insulin resistance. Recent evidence suggests that bromocriptine may produce these effects by altering central nervous system (CNS) regulation of metabolism. To determine whether or not the CNS plays a critical role in these bromocriptine-mediated effects on peripheral metabolism, we compared the metabolic responses to bromocriptine when administered peripherally versus centrally in naturally obese and glucose intolerant Syrian hamsters. Male hamsters (BW 194 +/- 5 g) were treated with bromocriptine or vehicle either intraperitoneally (i.p., 800 microgram/animal) or intracerebroventricularly (i.c.v., 1 microgram/animal) daily at 1 h after light onset for 14 days while held on 14-hour daily photoperiods. Glucose tolerance tests (GTTs, 3 g glucose/kg BW) were conducted after treatment. Compared to control animals, bromocriptine i.p. significantly reduced weight gain (11.7 vs. -2.4 g) and the areas under the glucose and insulin GTT curves by 29 and 48%, respectively. Similarly, compared with vehicle-treated controls, bromocriptine i.c.v. at 1 microgram/animal substantially reduced weight gain (8.7 vs. -6.3 g), the areas under the glucose and insulin GTT curves by 31 and 44% respectively, and the basal plasma insulin concentration by 41% (p < 0.05). Furthermore, both treatments significantly improved insulin-mediated suppression of hepatic glucose production during a hyperinsulinemic-euglycemic clamp. Thus, daily administration of bromocriptine at a very low dose i.c.v. replicates the metabolic effects of bromocriptine administered i.p. at a much higher dose. This finding demonstrates for the first time that the CNS is a critical target of bromocriptine's metabolic effects.
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Affiliation(s)
- S Luo
- Ergo Science Corp., Charlestown, Mass., USA.
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Liang Y, Lubkin M, Sheng H, Scislowski PW, Cincotta AH. Dopamine agonist treatment ameliorates hyperglycemia, hyperlipidemia, and the elevated basal insulin release from islets of ob/ob mice. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1405:1-13. [PMID: 9784590 DOI: 10.1016/s0167-4889(98)00092-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
One of the characteristics of obesity-associated diabetes is an elevated fasting plasma insulin concentration with a weak insulin secretory response to subsequent glucose stimulation. Evidence suggests that hyperglycemia and hyperlipidemia may contribute to the initiation and progression of this disordered islet glucose sensing. It has been proposed that reducing hyperglycemia and hyperlipidemia per se may improve islet glucose sensing. Here we studied glucose-dependent insulin release in islets isolated from ob/ob mice treated with dopamine agonists (bromocriptine and SKF38393, BC/SKF) which significantly reduced circulating glucose and lipid levels of ob/ob mice. Islets from BC/SKF-treated mice showed a marked decrease of the elevated basal insulin release to levels similar to lean mice. Such treatment also induced a higher secretory response to glucose stimulation compared with that in ob/ob mice with sustained hyperglycemia and hyperlipidemia. Similarly, when islets from untreated ob/ob mice were cultured for 7 days in 11 mM glucose in the absence of free fatty acid, the basal insulin release was significantly decreased and high glucose stimulated insulin release increased compared with that from islets cultured in medium containing 30 mM glucose and 2 mM oleate. The BC/SKF-induced reduction of elevated basal insulin release was associated with decreased hexokinase activity and basal cyclic AMP content in islet tissue. Our results demonstrate that dopamine agonist treatment improves basal insulin release in ob/ob mice and this effect may be mediated, in part, by a reduction of hyperglycemia and hyperlipidemia.
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Affiliation(s)
- Y Liang
- Ergoscience, Pre-clinical Research laboratory, 100 First Ave., 4th Floor, Charlestown, MA 02129, USA.
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Luo S, Meier AH, Cincotta AH. Bromocriptine reduces obesity, glucose intolerance and extracellular monoamine metabolite levels in the ventromedial hypothalamus of Syrian hamsters. Neuroendocrinology 1998; 68:1-10. [PMID: 9695933 DOI: 10.1159/000054344] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We examined whether reductions in body fat stores and insulin resistance in Syrian hamsters induced by bromocriptine are associated with reductions in daily norepinephrine (NE) and serotonin activities as indicated by their extracellular metabolite levels in the ventromedial hypothalamus (VMH). High levels of these monoamines within the VMH have been suspected to induce obesity and insulin resistance. Microdialysate samples from the VMH of freely moving obese male hamsters (BW: 208 +/- 5 g) were collected hourly over a 25-hour period before bromocriptine treatment, during the first day of and after 2 weeks of bromocriptine treatment (800 microg/animal daily, i.p.), and body composition and glucose tolerance analyses were conducted before and after 2 weeks of treatments. The microdialysate samples were analyzed by HPLC for metabolites of serotonin: 5-hydroxy-indoleacetic acid (5-HIAA), NE: 3-methoxy-4-hydroxy-phenylglycol (MHPG), and dopamine: homovanillic acid (HVA). Bromocriptine treatment for 14 days significantly reduced body fat by 60% and areas under the glucose and insulin curves during a glucose tolerance test by 50 and 46%, respectively. Concurrently, extracellular VMH contents of 5-HIAA, MHPG, and HVA were reduced by 50, 29 and 66%, respectively (p < 0.05). Similarly, VMH 5-HIAA and MHPG contents were 48 and 44% less, respectively (p < 0.05), in naturally glucose-tolerant hamsters compared with naturally glucose-intolerant hamsters. Bromocriptine induced reductions of body fat, and improvements in glucose intolerance may result in part from its ability to decrease serotonin and NE activities in the VMH.
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Affiliation(s)
- S Luo
- Ergo Science Corporation, Charlestown, Mass 02129, USA.
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Cincotta AH, Tozzo E, Scislowski PW. Bromocriptine/SKF38393 treatment ameliorates obesity and associated metabolic dysfunctions in obese (ob/ob) mice. Life Sci 1997; 61:951-6. [PMID: 9296333 DOI: 10.1016/s0024-3205(97)00599-7] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
It has been postulated that dopaminergic activities comprise a major functional component of a central regulatory system for metabolism which can be manipulated by dopamine modulating drugs. The present study is aimed at delineating the role and importance of pharmacological dopaminergic activation in the regulation of metabolism during obesity and diabetes. We treated C57BL/6J ob/ob mice for 2 weeks with bromocriptine (dopamine D2 agonist), SKF38393 (dopamine D1 agonist), both drugs combined or vehicle and monitored the effects of such treatment on body composition, food consumption, and serum metabolites. Bromocriptine and SKF38393 individually produced moderate improvements in obesity, hyperglycemia, and hyperinsulinemia. However, a combination of bromocriptine plus SKF38393 resulted in major reductions in body weight (7.5 g), body fat (40%), food consumption (42%), and serum concentrations of glucose (59%), triglyceride (37%), free fatty acid (45%) and insulin (49%) while increasing protein mass (8%). These results indicate that regulatory components of metabolism in the ob/ob mouse are modulated by and/or are comprised of dopaminergic activities. Importantly, dopaminergic D1/D2 receptor coactivation maximizes this dopaminergic response (i.e., improvement of metabolic abnormalities) in these mice.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/therapeutic use
- Animals
- Body Composition/drug effects
- Body Weight/drug effects
- Bromocriptine/pharmacology
- Bromocriptine/therapeutic use
- Dopamine Agonists/pharmacology
- Dopamine Agonists/therapeutic use
- Feeding Behavior/drug effects
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Obese
- Obesity/drug therapy
- Obesity/metabolism
- Receptors, Dopamine D1/agonists
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Affiliation(s)
- A H Cincotta
- Ergo Science Development Corporation, Charlestown, MA 02129, USA
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Abstract
Bromocriptine (BC), an ergot alkaloid with wide therapeutic use in humans, has been shown to inhibit proliferation of several abnormally hyperproliferative cells in vivo and in vitro. In the present study, direct effects of BC on mitogen-stimulated proliferation of rat vascular smooth muscle cells (VSMC) (A7r5 cells) and human aortic smooth muscle cells (HAOSMC) were examined in vitro. Twenty-four hour proliferative responses of quiescent A7r5 cells and HAOSMC to a variety of mitogens in the presence or absence of BC were determined by quantifying the incorporation of 3H-thymidine into DNA. BC at 1 microM inhibited the responses of A7r5 cells to various concentrations of fetal calf serum (FCS) by 50-70% without affecting the ED50 of FCS (2%). BC dose dependently inhibited the proliferation of A7r5 cells and HAOSMC stimulated by 2% FCS, with 52% inhibition at 1 and 0.1 microM, respectively. BC at 1 microM also completely inhibited the maximal mitogenic responses of A7r5 cells to prolactin, platelet-derived growth factor, insulin-like growth factor, and phorbol mysterate acetate (PMA), and BC at 1 microM completely inhibited the mitogenic response of HAOSMC to PMA. BC is a dopamine D2 agonist, a noradrenergic alpha 2 agonist, and an .alpha 1 antagonist, but the inhibitory effects of BC on A7r5 cell proliferation could not be mimicked by the specific D2 agonists, LY162502 and LY171555; the alpha 2 agonist, clonidine; or the alpha 1 antagonist, WB-4101. Neither dopamine nor the D2 agonist, LY162502, could inhibit HAOSMC proliferation induced by FCS. The PMA-induced stimulation of protein kinase C (PKC), a positive regulator of mitogenesis, could be completely blocked in A7r5 cells and HAOSMC by 1 and 0.1 microM BC, respectively. However, FPCS (2%)-induced activation of PKC in A7r5 cells and HAOSMC could only be blocked by 61 and 19% by BC (1 microM for A7r5 cells and 0.1 microM for HAOSMC), respectively. Given the existing evidence that BC reduces the severity of several other pathological conditions, such as insulin resistance, inflammation, and hyperlipidemia, which potentiate vascular disease, the current findings further suggest that BC use in the treatment of atherosclerosis and/or restenosis deserves further investigation.
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Affiliation(s)
- Y Zhang
- Ergo Science Development Corporation, Charlestown, MA 02129, USA
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Abstract
Numerous endocrine alterations are associated with obesity (Table 1). The majority of the alterations are secondary to obesity and must be considered simply associated and potentially in the pathogenesis of the complications of obesity. The discovery of new endocrine peptides such as leptin that signal body fat content will increase our understanding of the regulation of body fat content. As a result, therapies will most certainly be developed that are directly targeted at the alterations in endocrine function.
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Affiliation(s)
- S R Smith
- Inpatient Metabolic Unit, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, USA
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Korneyev AY, Cincotta AH. Identification of hepatic, non-monoamine, dihydroergocryptine binding sites with significant gender differences. Life Sci 1996; 58:241-8. [PMID: 8786706 DOI: 10.1016/0024-3205(96)00053-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
High affinity [3H] dihydroergocryptine binding sites different from alpha1/alpha2-adreno, dopamine or serotonin receptors were detected in a crude membrane fraction from hamster liver by radioligand binding filtration assay. The binding was saturable and reversible, as well as time and protein dependent. Scatchard analysis revealed a single population of binding sites with Kd 3.8 +/- 0.9 nM and Bmax = 675 +/- 130 pmol/g tissue (mean +/- S.E.M., n=6) in the male hamster crude liver membrane fraction. In the female liver membranes the Kd value was 4.4 + 1.2 nM and Bmax = 1025 +/- 190 pmol/g tissue (mean + S.E.M., n = 6). Differences between males and females in Bmax values were significant (P < 0.01). The most potent inhibitors of [3H] dihydroergocryptine binding were bromocriptine > ergotamine > dihydroergocryptine > dihydroergocristine > alpha ergocristine > dihidroergotamine > ergocornine > ergocristine > nicardipine > (+) butaclamol > PK 11195 > nitrendipine > domperidone > (-)butaclamol (in order of decreasing affinity). The described type of dihydroergocryptine binding sites was not detected in hamster brain, kidney, spleen or lungs. Obtained data support the concept that some ergot-derivatives may induce metabolic effects in the liver through peripheral mechanisms other than those, mediated by alpha-adrenoreceptors.
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