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Wagner R, Eckstein SS, Fritsche L, Prystupa K, Hörber S, Häring HU, Birkenfeld AL, Peter A, Fritsche A, Heni M. Postprandial Dynamics of Proglucagon Cleavage Products and Their Relation to Metabolic Health. Front Endocrinol (Lausanne) 2022; 13:892677. [PMID: 35872982 PMCID: PMC9297683 DOI: 10.3389/fendo.2022.892677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/24/2022] [Indexed: 11/20/2022] Open
Abstract
INTRODUCTION While oral glucose ingestion typically leads to a decrease in circulating glucagon levels, a substantial number of persons display stable or rising glucagon concentrations when assessed by radioimmunoassay (RIA). However, these assays show cross-reactivity to other proglucagon cleavage products. Recently, more specific assays became available, therefore we systematically assessed glucagon and other proglucagon cleavage products and their relation to metabolic health. RESEARCH DESIGN AND METHODS We used samples from 52 oral glucose tolerance tests (OGTT) that were randomly selected from persons with different categories of glucose tolerance in an extensively phenotyped study cohort. RESULTS Glucagon concentrations quantified with RIA were non-suppressed at 2 hours of the OGTT in 36% of the samples. Non-suppressors showed lower fasting glucagon levels compared to suppressors (p=0.011). Similar to RIA measurements, ELISA-derived fasting glucagon was lower in non-suppressors (p<0.001). Glucagon 1-61 as well as glicentin and GLP-1 kinetics were significantly different between suppressors and non-suppressors (p=0.004, p=0.002, p=0.008 respectively) with higher concentrations of all three hormones in non-suppressors. Levels of insulin, C-peptide, and free fatty acids were comparable between groups. Non-suppressors were leaner and had lower plasma glucose concentrations (p=0.03 and p=0.047, respectively). Despite comparable liver fat content and insulin sensitivity (p≥0.3), they had lower 2-hour post-challenge glucose (p=0.01). CONCLUSIONS Glucagon 1-61, glicentin and GLP-1 partially account for RIA-derived glucagon measurements due to cross-reactivity of the assay. However, this contribution is small, since the investigated proglucagon cleavage products contribute less than 10% to the variation in RIA measured glucagon. Altered glucagon levels and higher post-challenge incretins are associated with a healthier metabolic phenotype.
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Affiliation(s)
- Robert Wagner
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD), Tübingen, Germany
- Department of Internal Medicine IV, Division of Diabetology, Endocrinology, and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany
- Department of Endocrinology and Diabetology, Medical Faculty and University Hospital, Heinrich Heine University, Düsseldorf, Germany
- Institute for Clinical Diabetology, German Diabetes Center (DDZ), Leibniz Center for Diabetes Research at Heinrich-Heine University, Düsseldorf, Germany
| | - Sabine S. Eckstein
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD), Tübingen, Germany
| | - Louise Fritsche
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD), Tübingen, Germany
| | - Katsiaryna Prystupa
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD), Tübingen, Germany
- Department of Internal Medicine IV, Division of Diabetology, Endocrinology, and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Sebastian Hörber
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD), Tübingen, Germany
- Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tübingen, Tübingen, Germany
| | - Hans-Ulrich Häring
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD), Tübingen, Germany
- Department of Internal Medicine IV, Division of Diabetology, Endocrinology, and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Andreas L. Birkenfeld
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD), Tübingen, Germany
- Department of Internal Medicine IV, Division of Diabetology, Endocrinology, and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Andreas Peter
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD), Tübingen, Germany
- Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tübingen, Tübingen, Germany
| | - Andreas Fritsche
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD), Tübingen, Germany
- Department of Internal Medicine IV, Division of Diabetology, Endocrinology, and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Martin Heni
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD), Tübingen, Germany
- Department of Internal Medicine IV, Division of Diabetology, Endocrinology, and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany
- Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tübingen, Tübingen, Germany
- Division of Endocrinology and Diabetology, Department of Internal Medicine 1, University Hospital Ulm, Ulm, Germany
- *Correspondence: Martin Heni,
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Alexiadou K, Cuenco J, Howard J, Wewer Albrechtsen NJ, Ilesanmi I, Kamocka A, Tharakan G, Behary P, Bech PR, Ahmed AR, Purkayastha S, Wheller R, Fleuret M, Holst JJ, Bloom SR, Khoo B, Tan TMM. Proglucagon peptide secretion profiles in type 2 diabetes before and after bariatric surgery: 1-year prospective study. BMJ Open Diabetes Res Care 2020; 8:8/1/e001076. [PMID: 32209584 PMCID: PMC7103850 DOI: 10.1136/bmjdrc-2019-001076] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 01/20/2020] [Accepted: 02/07/2020] [Indexed: 12/18/2022] Open
Abstract
INTRODUCTION Hyperglucagonemia is a key pathophysiological driver of type 2 diabetes. Although Roux-en-Y gastric bypass (RYGB) is a highly effective treatment for diabetes, it is presently unclear how surgery alters glucagon physiology. The aim of this study was to characterize the behavior of proglucagon-derived peptide (glucagon, glucagon-like peptide-1 (GLP-1), oxyntomodulin, glicentin) secretion after RYGB surgery. RESEARCH DESIGN AND METHODS Prospective study of 19 patients with obesity and pre-diabetes/diabetes undergoing RYGB. We assessed the glucose, insulin, GLP-1, glucose-dependent insulinotropic peptide (GIP), oxyntomodulin, glicentin and glucagon responses to a mixed-meal test (MMT) before and 1, 3 and 12 months after surgery. Glucagon was measured using a Mercodia glucagon ELISA using the 'Alternative' improved specificity protocol, which was validated against a reference liquid chromatography combined with mass spectrometry method. RESULTS After RYGB, there were early improvements in fasting glucose and glucose tolerance and the insulin response to MMT was accelerated and amplified, in parallel to significant increases in postprandial GLP-1, oxyntomodulin and glicentin secretion. There was a significant decrease in fasting glucagon levels at the later time points of 3 and 12 months after surgery. Glucagon was secreted in response to the MMT preoperatively and postoperatively in all patients and there was no significant change in this postprandial secretion. There was no significant change in GIP secretion. CONCLUSIONS There is a clear difference in the dynamics of secretion of proglucagon peptides after RYGB. The reduction in fasting glucagon secretion may be one of the mechanisms driving later improvements in glycemia after RYGB. TRIAL REGISTRATION NUMBER NCT01945840.
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Affiliation(s)
- Kleopatra Alexiadou
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Joyceline Cuenco
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - James Howard
- Drug Development Solutions, LGC Bioscience, Fordham, Cambridgeshire, UK
| | - Nicolai Jacob Wewer Albrechtsen
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
- NNF Center for Protein Research, University of Copenhagen Faculty of Health and Medical Sciences, Copenhagen, Denmark
| | - Ibiyemi Ilesanmi
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Anna Kamocka
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - George Tharakan
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Preeshila Behary
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Paul R Bech
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Ahmed R Ahmed
- Department of Surgery and Cancer, Imperial College London, London, UK
| | | | - Robert Wheller
- Drug Development Solutions, LGC Bioscience, Fordham, Cambridgeshire, UK
| | - Matthieu Fleuret
- Drug Development Solutions, LGC Bioscience, Fordham, Cambridgeshire, UK
| | - Jens Juul Holst
- Department of Biomedical Sciences and the NNF Center for Basic Metabolic Research, University of Copenhagen Panum Institute, Copenhagen, Denmark
| | - Stephen R Bloom
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Bernard Khoo
- Division of Medicine, University College London, London, UK
| | - Tricia M-M Tan
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
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Raffort J, Lareyre F, Massalou D, Fénichel P, Panaïa-Ferrari P, Chinetti G. Insights on glicentin, a promising peptide of the proglucagon family. Biochem Med (Zagreb) 2017; 27:308-324. [PMID: 28736498 PMCID: PMC5508206 DOI: 10.11613/bm.2017.034] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 04/11/2017] [Indexed: 12/25/2022] Open
Abstract
Glicentin is a proglucagon-derived peptide mainly produced in the L-intestinal cells. While the roles of other members of the proglucagon family including glucagon-like peptide 1, glucagon-like peptide 2 and oxyntomodulin has been well studied, the functions and variation of glicentin in human are not fully understood. Experimental and clinical studies have highlighted its role in both intestinal physiology and glucose metabolism, pointing to its potential interest in a wide range of pathological states including gastrointestinal and metabolic disorders. Due to its structure presenting many similarities with the other proglucagon-derived peptides, its measurement is technically challenging. The recent commercialization of specific detection methods has offered new opportunities to go further in the understanding of glicentin physiology. Here we summarize the current knowledge on glicentin biogenesis and physiological roles. In the limelight of clinical studies investigating glicentin variation in human, we discuss future directions for potential applications in clinical practice.
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Affiliation(s)
- Juliette Raffort
- Clinical Chemistry Laboratory, University Hospital of Nice, Nice, France.,Université Côte d'Azur, Institute for Research on Cancer and Aging, Nice, France
| | - Fabien Lareyre
- Université Côte d'Azur, Institute for Research on Cancer and Aging, Nice, France.,Department of Vascular Surgery, University Hospital of Nice, Nice, France
| | - Damien Massalou
- Department of General Surgery and Digestive Cancerology, University Hospital of Nice, Nice, France
| | - Patrick Fénichel
- Department of Endocrinology, University Hospital of Nice, Nice, France
| | - Patricia Panaïa-Ferrari
- Clinical Chemistry Laboratory, University Hospital of Nice, Nice, France.,Université Côte d'Azur, Institute for Research on Cancer and Aging, Nice, France
| | - Giulia Chinetti
- Clinical Chemistry Laboratory, University Hospital of Nice, Nice, France.,Université Côte d'Azur, Institute for Research on Cancer and Aging, Nice, France
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Pellissier S, Bonaz B. The Place of Stress and Emotions in the Irritable Bowel Syndrome. VITAMINS AND HORMONES 2016; 103:327-354. [PMID: 28061975 DOI: 10.1016/bs.vh.2016.09.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Our emotional state can have many consequences on our somatic health and well-being. Negative emotions such as anxiety play a major role in gut functioning due to the bidirectional communications between gut and brain, namely, the brain-gut axis. The irritable bowel syndrome (IBS), characterized by an unusual visceral hypersensitivity, is the most common disorder encountered by gastroenterologists. Among the main symptoms, the presence of current or recurrent abdominal pain or discomfort associated with bloating and altered bowel habits characterizes this syndrome that could strongly alter the quality of life. This chapter will present the physiopathology of IBS and explain how stress influences gastrointestinal functions (permeability, motility, microbiota, sensitivity, secretion) and how it could be predominantly involved in IBS. This chapter will also describe the role of the autonomic nervous system and the hypothalamic-pituitary axis through vagal tone and cortisol homeostasis. An analysis is made about how emotions and feelings are involved in the disruption of homeostasis, and we will see to what extent the balance between vagal tone and cortisol may reflect dysfunctions of the brain-gut homeostasis. Finally, the interest of therapeutic treatments focused on stress reduction and vagal tone enforcement is discussed.
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Affiliation(s)
- S Pellissier
- Laboratoire Interuniversitaire de Psychologie, Personnalité, Cognition, Changement Social, Université Savoie Mont-Blanc, Chambéry, France.
| | - B Bonaz
- Clinique Universitaire d'Hépato-Gastroentérologie, CHU de Grenoble, Grenoble 09, France; Université Grenoble Alpes, Grenoble Institut des Neurosciences, Fonctions Cérébrales et Neuromodulation, INSERM, Grenoble 09, France
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Manell H, Staaf J, Manukyan L, Kristinsson H, Cen J, Stenlid R, Ciba I, Forslund A, Bergsten P. Altered Plasma Levels of Glucagon, GLP-1 and Glicentin During OGTT in Adolescents With Obesity and Type 2 Diabetes. J Clin Endocrinol Metab 2016; 101:1181-9. [PMID: 26745255 DOI: 10.1210/jc.2015-3885] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
CONTEXT Proglucagon-derived hormones are important for glucose metabolism, but little is known about them in pediatric obesity and type 2 diabetes mellitus (T2DM). OBJECTIVE Fasting and postprandial levels of proglucagon-derived peptides glucagon, GLP-1, and glicentin in adolescents with obesity across the glucose tolerance spectrum were investigated. DESIGN This was a cross-sectional study with plasma hormone levels quantified at fasting and during an oral glucose tolerance test (OGTT). SETTING This study took place in a pediatric obesity clinic at Uppsala University Hospital, Sweden. PATIENTS AND PARTICIPANTS Adolescents with obesity, age 10-18 years, with normal glucose tolerance (NGT, n = 23), impaired glucose tolerance (IGT, n = 19), or T2DM (n = 4) and age-matched lean adolescents (n = 19) were included. MAIN OUTCOME MEASURES Outcome measures were fasting and OGTT plasma levels of insulin, glucagon, active GLP-1, and glicentin. RESULTS Adolescents with obesity and IGT had lower fasting GLP-1 and glicentin levels than those with NGT (0.25 vs 0.53 pM, P < .05; 18.2 vs 23.6 pM, P < .01) and adolescents with obesity and T2DM had higher fasting glucagon levels (18.1 vs 10.1 pM, P < .01) than those with NGT. During OGTT, glicentin/glucagon ratios were lower in adolescents with obesity and NGT than in lean adolescents (P < .01) and even lower in IGT (P < .05) and T2DM (P < .001). CONCLUSIONS Obese adolescents with IGT have lowered fasting GLP-1 and glicentin levels. In T2DM, fasting glucagon levels are elevated, whereas GLP-1 and glicentin levels are maintained low. During OGTT, adolescents with obesity have more products of pancreatically than intestinally cleaved proglucagon (ie, more glucagon and less GLP-1) in the plasma. This shift becomes more pronounced when glucose tolerance deteriorates.
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Affiliation(s)
- Hannes Manell
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Johan Staaf
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Levon Manukyan
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Hjalti Kristinsson
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Jing Cen
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Rasmus Stenlid
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Iris Ciba
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Anders Forslund
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Peter Bergsten
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
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Abstract
From proglucagon, at least six final biologically active peptides are produced by tissue-specific post-translational processing. While glucagon and GLP-1 are the subject of permanent studies, the four others are usually left in the shadow, in spite of their large biological interest. The present review is devoted to oxyntomodulin and miniglucagon, not forgetting glicentin, although much less is known about it. Oxyntomodulin (OXM) and glicentin are regulators of gastric acid and hydromineral intestinal secretions. OXM is also deeply involved in the control of food intake and energy expenditure, properties that make this peptide a credible treatment of obesity if the question of administration is solved, as for any peptide. Miniglucagon, the C-terminal undecapeptide of glucagon which results from a secondary processing of original nature, displays properties antagonistic to that of the mother-hormone glucagon: (a) it inhibits glucose-, glucagon- and GLP-1-stimulated insulin release at sub-picomolar concentrations, (b) it reduces the in vivo insulin response to glucose with no change in glycemia, (c) it displays insulin-like properties at the cellular level using only a part of the pathway used by insulin, making it a good basis for developing a pharmacological workaround of insulin resistance.
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Affiliation(s)
| | - Stéphane Dalle
- INSERM, Research-Pathophysiology of the Pancreatic β Cell, Institute of Functional Genomic, INSERM U 661, CNRS UMR 5203, Universities Montpellier 1 & 2, Montpellier, France.
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Abstract
GLP-1 receptors are expressed in the brain, especially in the regions responsible for the regulation of food intake, and intracerebroventricular injection of GLP-1 results in inhibition of food intake. Peripheral administration of GLP-1 dose-dependently enhances satiety and reduces food intake in normal and obese subjects as well as in type 2 diabetic patients. So far, the mechanisms by which GLP-1 exerts its effects are not completely clear. Interactions with neurons in the gastrointestinal tract or possibly direct access to the brain through the blood-brain barrier as observed in rats are possible and discussed in this chapter as well as a novel hypothesis based on the finding that GLP-1 is also expressed in taste cells. Finally, the role of GLP-1 receptor agonists as a possible treatment option in obesity is discussed as well as the role of GLP-1 in the effects of bariatric surgery on adiposity and glucose homeostasis.
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Abstract
Desde o descobrimento da leptina, avanços consideráveis foram obtidos na caracterização dos mecanismos hipotalâmicos do controle da ingestão alimentar e, atualmente, a oxintomodulina é reconhecida como um regulador da homeostase energética. O presente artigo de revisão enfoca algumas das mais relevantes inter-relações do hormônio oxintomodulina com o apetite, a homeostase energética e aspectos de seu papel na bioquímica e fisiologia nutricional. A oxintomodulina é um peptídeo intestinal anorexígeno produzido pelas células L do intestino. Recentes estudos têm demonstrado que em longo prazo a administração de oxintomodulina reduz a ingestão alimentar e o ganho de peso. Pesquisas em humanos têm verificado que o seu uso reduz o consumo energértico em 25%. Portanto, a oxintomodulina representa uma potente terapia anti-obesidade. Entretanto, o mecanismo de ação da oxintomodulina ainda é desconhecido. Atuais evidências sugerem que tem ação via receptor do peptídeo semelhante ao glucagon 1. Além disso, a literatura mostra que, juntamente com a adoção de hábitos saudáveis e a mudança do estilo de vida, a oxintomodulina pode proporcionar menor avanço da obesidade.
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Bataille D. Pro-protein convertases in intermediary metabolism: islet hormones, brain/gut hormones and integrated physiology. J Mol Med (Berl) 2007; 85:673-84. [PMID: 17356847 DOI: 10.1007/s00109-007-0167-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Revised: 01/18/2007] [Accepted: 01/25/2007] [Indexed: 11/24/2022]
Abstract
Many peptide hormones implicated in the regulation of intermediary metabolism arise from larger precursors called prohormones. These precursors are cut into pieces by proprotein convertases, more precisely those called prohormone convertases (PCs) that cleave at the C terminus of basic doublets. The remaining basic amino acids are eliminated by a specialized carboxypeptidase, leading to the active hormone. This processing may provide, from a single precursor, several peptides with different biological activities depending on the site(s) of cleavage on the precursor. When the processing is tissue-specific, this mechanism allows to produce, from a single protein, different sets of hormones depending on the tissue considered, leading to novel regulatory processes. The archetype of such a pluripotent prohormone in the field of intermediary metabolism is pro-glucagon that, when cut by PC1 in intestinal L cells, produces four different peptides with different specificities [glicentin, oxyntomodulin (OXM), glucagon-like peptide-1, and glucagon-like peptide-2], whereas, when cut by PC2 in the alpha cells of the endocrine pancreas, glucagon is produced and, through the supplementary action of NRD convertase, a fragment of glucagon (miniglucagon) with original properties.
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Affiliation(s)
- Dominique Bataille
- Inserm U376, CHU Arnaud-de-Villeneuve, 34295, Montpellier Cedex 05, France.
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Grudell ABM, Camilleri M. The role of peptide YY in integrative gut physiology and potential role in obesity. Curr Opin Endocrinol Diabetes Obes 2007; 14:52-7. [PMID: 17940420 DOI: 10.1097/med.0b013e3280123119] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE OF REVIEW Obesity is an increasing global epidemic. Several central and peripheral hormones and neurotransmitters are involved in appetite control. Peptide YY (PYY) - one of the major anorexigenic (satiation-causing) gastrointestinal peptides - when administered peripherally, leads to decreased food intake and hunger scores. RECENT FINDINGS The vagus nerve, brainstem, and hypothalamus play an important role in PYY-mediated appetite control. In some studies, fasting and postprandial PYY levels are decreased in obese subjects. In others, levels are no different between obese and nonobese subjects. One study showed that obese subjects must consume more calories to increase PYY to levels seen in nonobese subjects. Surgical weight-loss procedures lead to increased fasting and postprandial PYY levels that are thought to contribute to weight loss achieved with these procedures. SUMMARY These findings lend some support for the association between PYY and obesity that could lead to possible new therapeutic options in obesity. PYY exerts anorexigenic effects; it is possible that surgical weight-loss procedures work synergistically with PYY to promote weight loss. Further investigation is needed to clarify whether PYY actually causes reduced calorie intake or whether the rate of food delivery to the ileo-colonic segment influences PYY levels, thus affecting satiation.
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Heijboer AC, Pijl H, Van den Hoek AM, Havekes LM, Romijn JA, Corssmit EPM. Gut-brain axis: regulation of glucose metabolism. J Neuroendocrinol 2006; 18:883-94. [PMID: 17076764 DOI: 10.1111/j.1365-2826.2006.01492.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Obesity and type II diabetes mellitus have reached epidemic proportions. From this perspective, knowledge about the regulation of satiety and food intake is more important than ever. The gut releases several peptides upon feeding, which affect hypothalamic pathways involved in the regulation of satiety and metabolism. Within the hypothalamus, there are complex interactions between many nuclei of which the arcuate nucleus is considered as one of the most important hypothalamic centres that regulates food intake. The neuropeptides, which are present in the hypothalamus and are involved in regulating food intake, also play a key role in regulating glucose metabolism and energy expenditure. In synchrony with the effects of those neuropeptides, gastrointestinal hormones also affect glucose metabolism and energy expenditure. In this review, the effects of the gastrointestinal hormones ghrelin, cholecystokinin, peptide YY, glucagon-like peptide, oxyntomodulin and gastric inhibitory polypeptide on glucose and energy metabolism are reviewed. These gut hormones affect glucose metabolism at different levels: by altering food intake and body weight, and thereby insulin sensitivity; by affecting gastric delay and gut motility, and thereby meal-related fluctuations in glucose levels; by affecting insulin secretion, and thereby plasma glucose levels, and by affecting tissue specific insulin sensitivity of glucose metabolism. These observations point to the notion of a major role of the gut-brain axis in the integrative physiology of whole body fuel metabolism.
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Affiliation(s)
- A C Heijboer
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands
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Abstract
The prevalence of obesity is increasing rapidly and the associated morbidity and mortality has led to an urgent need for potential therapeutic targets to reduce appetite and food intake. Gut hormones released after eating that coordinate digestive activity and promote satiety are novel potential treatments for obesity. Oxyntomodulin is a gut hormone that is produced by the L cells in the small intestine and reduces food intake. It is timely to review some of the original literature on oxyntomodulin, to evaluate what is already known about the peptide, and also to set the recent findings on its effects on food intake and bodyweight into context.Recent studies have shown that long-term peripheral administration of oxyntomodulin to rats leads to reduced food intake and reduced weight gain. Studies in humans have demonstrated that acute administration reduces food intake by 19%. When given preprandially by subcutaneous injection three times daily, oxyntomodulin resulted in a reduction in food intake and mean weight loss of 2.8kg over 4 weeks. Oxyntomodulin thus represents a potential therapy for obesity.The mechanism of action of oxyntomodulin is not known. Current evidence suggests that it acts via the glucagon-like peptide 1 (GLP-1) receptor. There may be an additional receptor in the gastric mucosa mediating its effects on gastric acid secretion. Although oxyntomodulin probably acts via the GLP-1 receptor, the two peptides differentially regulate food intake and energy expenditure in the mouse.Oxyntomodulin represents a potential therapy for obesity. Further work will help to clarify its mechanisms of action.
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Affiliation(s)
- Maralyn R Druce
- Department of Metabolic Medicine, Hammersmith Hospital, Imperial College London, London, UK
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Ayachi SE, Borie F, Magous R, Sasaki K, le Nguyen D, Bali JP, Millat B, Jarrousse C. Contraction induced by glicentin on smooth muscle cells from the human colon is abolished by exendin (9-39). Neurogastroenterol Motil 2005; 17:302-9. [PMID: 15787950 DOI: 10.1111/j.1365-2982.2004.00628.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
UNLABELLED Glicentin and glucagon-like peptide-1 (7-36) amide (GLP-1) are gut hormones released during digestion. Glicentin and GLP-1 slow down gastric emptying and glicentin can switch off the duodenojejunal fed motor pattern. The effect of glicentin on the motor activity of colon has never been reported in humans. Our aim was to determine if circular smooth muscle cells (SMC) from the human colon are target cells for glicentin or GLP-1, and if their motility is dependent upon these digestive hormones. METHODS Twenty-two resections were performed on patients operated for colon adenocarcinoma. The SMC were isolated from colonic circular muscle layer and cell contraction was assessed. RESULTS Glicentin caused a dose-related contraction of SMC, when GLP-1 determined a contraction of weak amplitude. Exendin-(9-39), described as a GLP-1 receptor antagonist, inhibited contraction due to glicentin or GLP-1. In contrast, on antral SMC from rabbit, GLP-1 exerts neither relaxation nor contraction; however, exendin-(9-39) dose dependently reduced the contractile activity of glicentin [glicentin EC(50) = 5 pM, exendin-(9-39) pA(2) = -9.36]. CONCLUSIONS The circular muscle from the human colon is a target tissue for glicentin and GLP-1. Whereas glicentin is a long-life digestive hormone which would contribute to segmental contraction, the biological activity of GLP-1 remains unknown on this tissue. On the digestive smooth muscle, exendin-(9-39) behaved as an antagonist for two members of the glucagon-receptor family, GLP-1 and glicentin.
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Affiliation(s)
- S E Ayachi
- Laboratory of Signalling of Normal and Tumoral Cells, Faculty of Pharmacy, University of Montpellier 1, 15 avenue Charles Flahault, 34093 Montpellier cedex 05, France
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