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Zhang J, Zheng Y, Martens L, Pfeiffer AFH. The Regulation and Secretion of Glucagon in Response to Nutrient Composition: Unraveling Their Intricate Mechanisms. Nutrients 2023; 15:3913. [PMID: 37764697 PMCID: PMC10536047 DOI: 10.3390/nu15183913] [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: 08/01/2023] [Revised: 08/31/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
Glucagon was initially regarded as a hyperglycemic substance; however, recent research has revealed its broader role in metabolism, encompassing effects on glucose, amino acids (AAs), and lipid metabolism. Notably, the interplay of glucagon with nutrient intake, particularly of AAs, and non-nutrient components is central to its secretion. Fasting and postprandial hyperglucagonemia have long been linked to the development and progression of type 2 diabetes (T2DM). However, recent studies have brought to light the positive impact of glucagon agonists on lipid metabolism and energy homeostasis. This review explores the multifaceted actions of glucagon, focusing on its regulation, signaling pathways, and effects on glucose, AAs, and lipid metabolism. The interplay between glucagon and other hormones, including insulin and incretins, is examined to provide a mechanistic understanding of its functions. Notably, the liver-α-cell axis, which involves glucagon and amino acids, emerges as a critical aspect of metabolic regulation. The dysregulation of glucagon secretion and its impact on conditions such as T2DM are discussed. The review highlights the potential therapeutic applications of targeting the glucagon pathway in the treatment of metabolic disorders.
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Affiliation(s)
- Jiudan Zhang
- The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou 310053, China;
- Department of Endocrinology, Diabetes and Nutrition, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (L.M.); (A.F.H.P.)
| | - Yang Zheng
- The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou 310053, China;
| | - Lisa Martens
- Department of Endocrinology, Diabetes and Nutrition, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (L.M.); (A.F.H.P.)
- Nutritional Science, University of Potsdam, 14469 Potsdam, Germany
| | - Andreas F. H. Pfeiffer
- Department of Endocrinology, Diabetes and Nutrition, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (L.M.); (A.F.H.P.)
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Kobayashi M, Satoh H, Matsuo T, Kusunoki Y, Tokushima M, Watada H, Namba M, Kitamura T. Plasma glucagon levels measured by sandwich ELISA are correlated with impaired glucose tolerance in type 2 diabetes. Endocr J 2020; 67:903-922. [PMID: 32448820 DOI: 10.1507/endocrj.ej20-0079] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Glucagon dysfunction as well as insulin dysfunction is associated with the pathogenesis of type 2 diabetes (T2DM). However, it is still unclear whether the measurement of plasma glucagon levels is useful in understanding the pathophysiology of T2DM. We recently reported that sandwich ELISA provides more accurate plasma glucagon values than conventional RIA in healthy subjects. Here we used sandwich ELISA as well as RIA to assess plasma glucagon levels, comparing them in T2DM patients and healthy subjects during oral glucose (OGTT) or meal tolerance tests (MTT). We confirmed that sandwich ELISA was able to detect more significant difference between healthy subjects and T2DM patients in the fasting levels and the response dynamics of plasma glucagon than RIA. We also found significant differences in the following glucagon parameters: (1) fasting glucagon, (2) the area under the curve (AUC) of glucagon in OGTT, and (3) the change in glucagon between 0 and 30 min (ΔGlucagon0-0.5h) in OGTT or MTT. Among these, the most apparent difference was ΔGlucagon0-0.5h in MTT. When we divided T2DM patients into two groups whose ΔGlucagon0-0.5h in MTT was either below or above the maximum value in healthy subjects, the group with higher ΔGlucagon0-0.5h showed more significant impairment of glucose tolerance. These results suggest that the assessment of plasma glucagon levels by sandwich ELISA might enhance our understanding of the pathophysiology of T2DM.
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Affiliation(s)
- Masaki Kobayashi
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
| | - Hiroaki Satoh
- Department of Metabolism & Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Toshihiro Matsuo
- Division of Diabetes, Endocrinology and Clinical Immunology Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Yoshiki Kusunoki
- Division of Diabetes, Endocrinology and Clinical Immunology Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | | | - Hirotaka Watada
- Department of Metabolism & Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Mitsuyoshi Namba
- Division of Diabetes, Endocrinology and Clinical Immunology Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
- Takarazuka City Hospital, Takarazuka, Hyogo, Japan
| | - Tadahiro Kitamura
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
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Stern JH, Smith GI, Chen S, Unger RH, Klein S, Scherer PE. Obesity dysregulates fasting-induced changes in glucagon secretion. J Endocrinol 2019; 243:149-160. [PMID: 31454790 PMCID: PMC6994388 DOI: 10.1530/joe-19-0201] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 08/27/2019] [Indexed: 01/06/2023]
Abstract
Hyperglucagonemia, a hallmark in obesity and insulin resistance promotes hepatic glucose output, exacerbating hyperglycemia and thus predisposing to the development type 2 diabetes. As such, glucagon signaling is a key target for new therapeutics to manage insulin resistance. We evaluated glucagon homeostasis in lean and obese mice and people. In lean mice, fasting for 24 h caused a rise in glucagon. In contrast, a decrease in serum glucagon compared to baseline was observed in diet-induced obese mice between 8 and 24 h of fasting. Fasting decreased serum insulin in both lean and obese mice. Accordingly, the glucagon:insulin ratio was unaffected by fasting in obese mice but increased in lean mice. Re-feeding (2 h) restored hyperglucagonemia in obese mice. Pancreatic perfusion studies confirm that fasting (16 h) decreases pancreatic glucagon secretion in obese mice. Consistent with our findings in the mouse, a mixed meal increased serum glucagon and insulin concentrations in obese humans, both of which decreased with time after a meal. Consequently, fasting and re-feeding less robustly affected glucagon:insulin ratios in obese compared to lean participants. The glucoregulatory disturbance in obesity may be driven by inappropriate regulation of glucagon by fasting and a static glucagon:insulin ratio.
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Affiliation(s)
- Jennifer H. Stern
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX
| | - Gordon I. Smith
- Center for Human Nutrition, Washington University School of Medicine, Saint Louis, MO
| | - Shiuwei Chen
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX
| | - Roger H. Unger
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX
| | - Samuel Klein
- Center for Human Nutrition, Washington University School of Medicine, Saint Louis, MO
| | - Philipp E. Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX
- Correspondence: , Telephone: (214) 648-8715, Fax: (214) 648-8720
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Lee M, Kim M, Park JS, Lee S, You J, Ahn CW, Kim KR, Kang S. Higher glucagon-to-insulin ratio is associated with elevated glycated hemoglobin levels in type 2 diabetes patients. Korean J Intern Med 2019; 34:1068-1077. [PMID: 28882024 PMCID: PMC6718759 DOI: 10.3904/kjim.2016.233] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Accepted: 06/26/2017] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND/AIMS The importance of α-cell dysfunction in the pathogenesis of type 2 diabetes has re-emerged recently. However, data on whether relative glucagon excess is present in clinical settings are scarce. We aimed to investigate associations between glucagon-to-insulin ratio and various metabolic parameters. METHODS A total of 451 patients with type 2 diabetes naïve to insulin treatment were recruited. Using glucagon-to-insulin ratio, we divided subjects into quartiles according to both fasting and postprandial glucagon-to-insulin ratios. RESULTS The mean age of the subjects was 58 years, with a mean body mass index of 25 kg/m2 . The patients in the highest quartile of glucagon-to-insulin ratio had higher glycated hemoglobin (HbA1c) levels. HbA1c levels were positively correlated with both fasting and postprandial glucagon-to-insulin ratios. Subjects in the highest quartile of postprandial glucagon-to-insulin ratio were more likely to exhibit uncontrolled hyperglycemia, even after adjusting for confounding factors (odds ratio, 2.730; 95% confidence interval, 1.236 to 6.028; p for trend < 0.01). CONCLUSION Hyperglucagonemia relative to insulin could contribute to uncontrolled hyperglycemia in type 2 diabetes patients.
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Affiliation(s)
- Minyoung Lee
- Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Minkyung Kim
- Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Jong Suk Park
- Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
- Severance Institute for Vascular and Metabolic Research, Yonsei University College of Medicine, Seoul, Korea
| | - Sangbae Lee
- Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Jihong You
- Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Chul Woo Ahn
- Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
- Severance Institute for Vascular and Metabolic Research, Yonsei University College of Medicine, Seoul, Korea
| | - Kyung Rae Kim
- Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Shinae Kang
- Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
- Severance Institute for Vascular and Metabolic Research, Yonsei University College of Medicine, Seoul, Korea
- Correspondence to Shinae Kang, M.D. Division of Endocrinology, Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul 06273, Korea Tel: +82-2-2019-3335 Fax: +82-2-3463-3882 E-mail:
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Murray M, Dordevic AL, Ryan L, Bonham MP. A Single-Dose of a Polyphenol-Rich Fucus Vesiculosus Extract is Insufficient to Blunt the Elevated Postprandial Blood Glucose Responses Exhibited by Healthy Adults in the Evening: A Randomised Crossover Trial. Antioxidants (Basel) 2019; 8:antiox8020049. [PMID: 30813480 PMCID: PMC6406275 DOI: 10.3390/antiox8020049] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 02/12/2019] [Accepted: 02/16/2019] [Indexed: 12/14/2022] Open
Abstract
When healthy adults consume carbohydrates at night, postprandial blood glucose responses are elevated and prolonged compared to daytime.Extended postprandial hyperglycaemia is a risk factor for type 2 diabetes. Polyphenols are bioactive secondary metabolites of plants and algae with potential to moderate postprandial glycaemia. This study investigated whether a polyphenol-rich alga (Fucus vesiculosus) extract moderated postprandial glycaemia in the evening in healthy adults. In a double blind, placebo-controlled, randomised three-way crossover trial, 18 participants consumed a polyphenol-rich extract, a cellulose placebo and rice flour placebo (7:15 p.m.) prior to 50 g available carbohydrate from bread (7:45 p.m.), followed by three hours of blood sampling to assess glucose and insulin. A subset of participants (n = 8) completed the same protocol once in the morning with only the cellulose placebo (7:15 a.m.). No effect of the polyphenol-rich extract was observed on postprandial glycaemia in the evening, compared with placebos, in the group as a whole. However, in females only, peak blood glucose concentration was reduced following the polyphenol-rich extract. In the subset analysis, as expected, participants exhibited elevated postprandial blood glucose in the evening compared with the morning following the cellulose placebo. This was the first study to investigate whether a polyphenol intervention moderated evening postprandial hyperglycaemia. The lowering effect observed in females suggests that this warrants further investigation.
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Affiliation(s)
- Margaret Murray
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill VIC 3168, Australia.
- School of Chemistry, Monash University, Clayton, VIC 3800, Australia.
| | - Aimee L Dordevic
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill VIC 3168, Australia.
| | - Lisa Ryan
- School of Science and Computing, Galway-Mayo Institute of Technology, Galway H91 T8NW, Ireland.
| | - Maxine P Bonham
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill VIC 3168, Australia.
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Jakubowicz D, Wainstein J, Ahren B, Landau Z, Bar-Dayan Y, Froy O. Fasting until noon triggers increased postprandial hyperglycemia and impaired insulin response after lunch and dinner in individuals with type 2 diabetes: a randomized clinical trial. Diabetes Care 2015. [PMID: 26220945 DOI: 10.2337/dc15-0761] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Skipping breakfast has been consistently associated with high HbA1c and postprandial hyperglycemia (PPHG) in patients with type 2 diabetes. Our aim was to explore the effect of skipping breakfast on glycemia after a subsequent isocaloric (700 kcal) lunch and dinner. RESEARCH DESIGN AND METHODS In a crossover design, 22 patients with diabetes with a mean diabetes duration of 8.4 ± 0.7 years, age 56.9 ± 1.0 years, BMI 28.2 ± 0.6 kg/m(2), and HbA1c 7.7 ± 0.1% (61 ± 0.8 mmol/mol) were randomly assigned to two test days: one day with breakfast, lunch, and dinner (YesB) and another with lunch and dinner but no breakfast (NoB). Postprandial plasma glucose, insulin, C-peptide, free fatty acids (FFA), glucagon, and intact glucagon-like peptide-1 (iGLP-1) were assessed. RESULTS Compared with YesB, lunch area under the curves for 0-180 min (AUC0-180) for plasma glucose, FFA, and glucagon were 36.8, 41.1, and 14.8% higher, respectively, whereas the AUC0-180 for insulin and iGLP-1 were 17% and 19% lower, respectively, on the NoB day (P < 0.0001). Similarly, dinner AUC0-180 for glucose, FFA, and glucagon were 26.6, 29.6, and 11.5% higher, respectively, and AUC0-180 for insulin and iGLP-1 were 7.9% and 16.5% lower on the NoB day compared with the YesB day (P < 0.0001). Furthermore, insulin peak was delayed 30 min after lunch and dinner on the NoB day compared with the YesB day. CONCLUSIONS Skipping breakfast increases PPHG after lunch and dinner in association with lower iGLP-1 and impaired insulin response. This study shows a long-term influence of breakfast on glucose regulation that persists throughout the day. Breakfast consumption could be a successful strategy for reduction of PPHG in type 2 diabetes.
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Affiliation(s)
- Daniela Jakubowicz
- Diabetes Unit, Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Holon, Israel Diabetes Unit, Department of Internal Medicine, Hospital de Clinicas Caracas, Central University of Venezuela, Caracas, Venezuela
| | - Julio Wainstein
- Diabetes Unit, Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Holon, Israel
| | - Bo Ahren
- Department of Clinical Sciences, Faculty of Medicine, Lund University, Lund, Sweden
| | - Zohar Landau
- Diabetes Unit, Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Holon, Israel
| | - Yosefa Bar-Dayan
- Diabetes Unit, Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Holon, Israel
| | - Oren Froy
- Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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Lefèbvre PJ, Paquot N, Scheen AJ. Inhibiting or antagonizing glucagon: making progress in diabetes care. Diabetes Obes Metab 2015; 17:720-5. [PMID: 25924114 DOI: 10.1111/dom.12480] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 04/27/2015] [Accepted: 04/27/2015] [Indexed: 01/07/2023]
Abstract
Absolute or relative hyperglucagonaemia has been recognized for years in all experimental or clinical forms of diabetes. It has been suggested that excess secretion of glucagon by the islet α cells is a direct consequence of intra-islet insulin secretory defects. Recent studies have shown that knockout of the glucagon receptor or administration of a monoclonal specific glucagon receptor antibody make insulin-deficient type 1 diabetic rodents thrive without insulin. These observations suggest that glucagon plays an essential role in the pathophysiology of diabetes and that targeting the α cell and glucagon are innovative approaches in the management of diabetes. Despite active research and identification of promising compounds, no one selective glucagon antagonist is presently used in the treatment of diabetes. Interestingly, besides insulin, several drugs used today in the management of diabetes appear to exert their effects, in part, by inhibiting glucagon secretion (glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, α-glucosidase inhibitors and, possibly, sulphonylureas) or glucagon action (metformin). The potential risks associated with total glucagon suppression include α-cell hyperplasia, increased mass of the pancreas, increased susceptibility to hepatosteatosis and hepatocellular injury and increased risk of hypoglycaemia, and these should be considered in the search and development of new compounds reducing glucagon receptor signalling. More than 40 years after its initial description, hyperglucagonaemia in diabetes can no longer be ignored or minimized, and its correction represents an attractive way to improve diabetes management.
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Affiliation(s)
- P J Lefèbvre
- Division of Diabetes, Nutrition and Metabolic Disorders, Department of Medicine, University of Liège, Liège, Belgium
| | - N Paquot
- Division of Diabetes, Nutrition and Metabolic Disorders, Department of Medicine, University of Liège, Liège, Belgium
| | - A J Scheen
- Division of Diabetes, Nutrition and Metabolic Disorders, Department of Medicine, University of Liège, Liège, Belgium
- Division of Clinical Pharmacology, Department of Medicine, University of Liège, Liège, Belgium
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Bagger JI, Knop FK, Lund A, Holst JJ, Vilsbøll T. Glucagon responses to increasing oral loads of glucose and corresponding isoglycaemic intravenous glucose infusions in patients with type 2 diabetes and healthy individuals. Diabetologia 2014; 57:1720-5. [PMID: 24879388 DOI: 10.1007/s00125-014-3264-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 04/28/2014] [Indexed: 12/01/2022]
Abstract
AIMS/HYPOTHESIS Type 2 diabetes is associated with hypersecretion of glucagon during an OGTT, whereas i.v. glucose suppresses glucagon levels. This suggests that type 2 diabetic hyperglucagonaemia may result from glucose stimulation of the gastrointestinal tract. We evaluated glucagon responses to increasing amounts of glucose given orally and corresponding isoglycaemic i.v. glucose infusions (IIGIs) in patients with type 2 diabetes and in healthy controls. METHODS Plasma glucagon responses were measured during three 4 h OGTTs with increasing loads of glucose (25 g, 75 g and 125 g) and three corresponding IIGIs in eight patients with type 2 diabetes (age [mean ± SEM] 57 ± 4 years; BMI 29.5 ± 1.0 kg/m(2); HbA1c 7.0 ± 0.3% [53 ± 2 mmol/mol]) and eight healthy individuals (age 57 ± 4 years; BMI 28.9 ± 0.7 kg/m(2); HbA1c 5.4 ± 0.1% [36 ± 1 mmol/mol]). RESULTS In healthy controls no difference in glucagon suppression during the first 45 min of the 25 g OGTT and the corresponding IIGI (-153 ± 35 vs -133 ± 24 min × pmol/l; p = NS) was observed, whereas patients with type 2 diabetes only exhibited significant glucagon suppression following IIGI (29 ± 27 vs -144 ± 20 min × pmol/l; p = 0.005). At higher oral glucose loads this difference increased and also became evident in healthy controls. CONCLUSIONS/INTERPRETATION In patients with type 2 diabetes increasing amounts of oral glucose elicit hypersecretion of glucagon, whereas corresponding IIGIs result in significant glucagon suppression; a phenomenon that is also observed in healthy individuals when larger glucose loads are ingested orally. This suggests that the hyperglucagonaemic response to oral glucose in type 2 diabetes may represent a pathological version of a gut-derived physiological phenomenon. TRIAL REGISTRATION ClinicalTrials.gov NCT00529048.
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Affiliation(s)
- Jonatan I Bagger
- Center for Diabetes Research, Department of Medicine, Gentofte Hospital, University of Copenhagen, Niels Andersens Vej 65, 2900, Hellerup, Denmark
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Christensen MB, Calanna S, Holst JJ, Vilsbøll T, Knop FK. Glucose-dependent insulinotropic polypeptide: blood glucose stabilizing effects in patients with type 2 diabetes. J Clin Endocrinol Metab 2014; 99:E418-26. [PMID: 24423311 DOI: 10.1210/jc.2013-3644] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
CONTEXT Patients with type 2 diabetes mellitus (T2DM) have clinically relevant disturbances in the effects of the hormone glucose-dependent insulinotropic polypeptide (GIP). OBJECTIVE We aimed to evaluate the importance of the prevailing plasma glucose levels for the effect of GIP on responses of glucagon and insulin and glucose disposal in patients with T2DM. DESIGN AND SETTING We performed a single center, placebo-controlled, cross-over, experimental study. PATIENTS We studied twelve patients with T2DM (age: 62 ± 1 years [mean ± SEM], body mass index: 29 ± 1 kg/m(2); glycosylated hemoglobin A1c: 6.5 ± 0.1% [48 ± 2 mmol/mol]). INTERVENTION We infused physiological amounts of GIP (2 pmol × kg(-1) × min(-1)) or saline. MAIN OUTCOME MEASURES We measured plasma concentrations of glucagon, glucose, insulin, C-peptide, intact GIP, and amounts of glucose needed to maintain glucose clamps. RESULTS During fasting glycemia (plasma glucose ∼8 mmol/L), GIP elicited significant increments in both insulin and glucagon levels, resulting in neutral effects on plasma glucose. During insulin-induced hypoglycemia (plasma glucose ∼3 mmol/L), GIP elicited a minor early-phase insulin response and increased glucagon levels during the initial 30 minutes, resulting in less glucose needed to be infused to maintain the clamp (29 ± 8 vs 49 ± 12 mg × kg(-1), P < .03). During hyperglycemia (1.5 × fasting plasma glucose ∼12 mmol/L), GIP augmented insulin secretion throughout the clamp, with slightly less glucagon suppression compared with saline, resulting in more glucose needed to maintain the clamp during GIP infusions (265 ± 21 vs 213 ± 13 mg × kg(-1), P < .001). CONCLUSIONS In patients with T2DM, GIP counteracts insulin-induced hypoglycemia, most likely through a predominant glucagonotropic effect. In contrast, during hyperglycemia, GIP increases glucose disposal through a predominant effect on insulin release.
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Affiliation(s)
- Mikkel B Christensen
- Diabetes Research Division (M.B.C., S.C., T.V., F.K.K.), Department of Medicine, Copenhagen University Hospital Gentofte, Hellerup DK-2900, Denmark; Department of Biomedical Sciences (J.J.H., M.B.C., F.K.K.), the Panum Institute; University of Copenhagen, DK-2100 Copenhagen, Denmark; and Department of Clinical and Molecular Biomedicine (S.C.), University of Catania, 95124 Catania, Italy
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10
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Knop FK, Vilsbøll T, Larsen S, Madsbad S, Holst JJ, Krarup T. Glucagon suppression during OGTT worsens while suppression during IVGTT sustains alongside development of glucose intolerance in patients with chronic pancreatitis. ACTA ACUST UNITED AC 2010; 164:144-50. [PMID: 20573586 DOI: 10.1016/j.regpep.2010.05.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 05/11/2010] [Accepted: 05/25/2010] [Indexed: 11/17/2022]
Abstract
AIMS To examine plasma glucagon responses to oral and intravenous (iv) glucose in patients with chronic pancreatitis (CP) and either normal glucose tolerance (NGT), secondary impaired glucose tolerance (IGT) or secondary diabetes mellitus (DM). METHODS Eleven patients with CP and NGT, 6 patients with CP and secondary IGT, 7 patients with CP and secondary non-insulin requiring DM, and 8 healthy subjects were examined with an oral glucose tolerance test (OGTT) and an iv glucose tolerance test (IVGTT). RESULTS In the CP groups, significant differences (increasing with the degree of glucose intolerance) in glucagon responses during the first hour of OGTT compared to IVGTT were observed (CP+NGT: -13 + or - 22 vs. -88 + or - 17, p = 0.02; CP+IGT: 3 + or - 17 vs. -87 + or - 19, p = 0.01; CP+DM: 94 + or - 27 vs. -78 + or - 16 1 h x pmol/l (mean + or - SEM), p<0.001). Glucagon was suppressed equally following OGTT and IVGTT in the healthy subjects (-103 + or - 22 vs. -131 + or - 19 1 h x pmol/l; p=NS). IVGTT suppressed glucagon similarly in all groups except for a slightly impaired suppression in the CP+DM-group compared to healthy subjects. CONCLUSIONS These results suggest that along with the development of secondary glucose intolerance in patients with CP, the suppression of glucagon by oral glucose is gradually lost and substituted by a paradoxical stimulation of secretion, while the suppression by iv glucose is maintained. This might indicate a glucagon stimulatory mechanism of gastrointestinal origin in CP patients.
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Affiliation(s)
- F K Knop
- Department of Internal Medicine F, Gentofte Hospital, University of Copenhagen, Denmark
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Abstract
Glucose homeostasis is regulated primarily by the opposing actions of insulin and glucagon, hormones that are secreted by pancreatic islets from beta-cells and alpha-cells, respectively. Insulin secretion is increased in response to elevated blood glucose to maintain normoglycemia by stimulating glucose transport in muscle and adipocytes and reducing glucose production by inhibiting gluconeogenesis in the liver. Whereas glucagon secretion is suppressed by hyperglycemia, it is stimulated during hypoglycemia, promoting hepatic glucose production and ultimately raising blood glucose levels. Diabetic hyperglycemia occurs as the result of insufficient insulin secretion from the beta-cells and/or lack of insulin action due to peripheral insulin resistance. Remarkably, excessive secretion of glucagon from the alpha-cells is also a major contributor to the development of diabetic hyperglycemia. Insulin is a physiological suppressor of glucagon secretion; however, at the cellular and molecular levels, how intraislet insulin exerts its suppressive effect on the alpha-cells is not very clear. Although the inhibitory effect of insulin on glucagon gene expression is an important means to regulate glucagon secretion, recent studies suggest that the underlying mechanisms of the intraislet insulin on suppression of glucagon secretion involve the modulation of K(ATP) channel activity and the activation of the GABA-GABA(A) receptor system. Nevertheless, regulation of glucagon secretion is multifactorial and yet to be fully understood.
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Affiliation(s)
- Pritpal Bansal
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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Chiarelli F, Di Marzio D. Peroxisome proliferator-activated receptor-gamma agonists and diabetes: current evidence and future perspectives. Vasc Health Risk Manag 2008; 4:297-304. [PMID: 18561505 PMCID: PMC2496982 DOI: 10.2147/vhrm.s993] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Since their initial availability in 1997, the thiazolidinediones (TZDs) have become one of the most commonly prescribed classes of medications for type 2 diabetes. In addition to glucose control, the TZDs have a number of pleiotropic effects on myriad traditional and non-traditional risk factors for diabetes. TZDs may benefit cardiovascular parameters, such as lipids, blood pressure, inflammatory biomarkers, endothelial function and fibrinolytic state. In this review, we summarise the experimental, preclinical and clinical data regarding the effects of the TZDs in conditions for which they are indicated and discuss their potential in the treatment of other conditions.
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Jayapaul MK, Walker M. Hyperglucagonaemia is not a primary metabolic defect in non-diabetic first-degree relatives from Type 2 diabetic families. Diabet Med 2007; 24:1050-1. [PMID: 17725709 DOI: 10.1111/j.1464-5491.2007.02207.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Knop FK, Vilsbøll T, Madsbad S, Holst JJ, Krarup T. Inappropriate suppression of glucagon during OGTT but not during isoglycaemic i.v. glucose infusion contributes to the reduced incretin effect in type 2 diabetes mellitus. Diabetologia 2007; 50:797-805. [PMID: 17225124 DOI: 10.1007/s00125-006-0566-z] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2006] [Accepted: 11/17/2006] [Indexed: 12/25/2022]
Abstract
AIMS/HYPOTHESIS We investigated glucagon responses during OGTT and isoglycaemic i.v. glucose infusion, respectively, to further elucidate the mechanisms behind the glucose intolerance in patients with type 2 diabetes. MATERIALS AND METHODS Ten patients (eight men) with type 2 diabetes (age: 64 [51-80] years; BMI: 23 [21-26] kg/m(2); HbA(1c): 6.9 [6.2-8.7]%, values mean [range]) and ten control subjects matched for sex, age and BMI were studied. Blood was sampled on two separate days following a 4-h 50-g OGTT and an isoglycaemic i.v. glucose infusion, respectively. RESULTS Isoglycaemia during the 2 days was obtained in both groups. In the control subjects no difference in glucagon suppression during the first 45 min of OGTT and isoglycaemic i.v. glucose infusion (-36 +/- 12 vs -64 +/- 23 mmol/l x 45 min; p = NS) was observed, whereas in the group of patients with type 2 diabetes significant glucagon suppression only occurred following isoglycaemic i.v. glucose infusion (-63 +/- 21 vs 10 +/- 16 mmol/l x 45 min; p = 0.002). The incretin effect was significantly reduced in patients with type 2 diabetes compared with control subjects, but no significant differences in the secretion of glucagon-like peptide-1 or glucose-dependent insulinotropic polypeptide between the two groups during OGTT or isoglycaemic i.v. glucose infusion, respectively, could explain this. CONCLUSIONS/INTERPRETATION Attenuated and delayed glucagon suppression in patients with type 2 diabetes occurs after oral ingestion of glucose, while isoglycaemic i.v. administration of glucose results in normal suppression of glucagon. We suggest that this phenomenon contributes both to the glucose intolerance and to the reduced incretin effect observed in patients with type 2 diabetes.
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Affiliation(s)
- F K Knop
- Department of Internal Medicine F, Gentofte Hospital, University of Copenhagen, Niels Andersens Vej 65, DK-2900, Hellerup, Denmark.
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Ahrén B. Glucagon secretion in relation to insulin sensitivity in healthy subjects. Diabetologia 2006; 49:117-22. [PMID: 16362283 DOI: 10.1007/s00125-005-0056-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2005] [Accepted: 09/12/2005] [Indexed: 10/25/2022]
Abstract
AIMS/HYPOTHESIS The study evaluated whether glucagon secretion is regulated by changes in insulin sensitivity under normal conditions. MATERIALS AND METHODS A total of 155 healthy women with NGT (aged 53-70 years) underwent a glucose-dependent arginine-stimulation test for evaluation of glucagon secretion. Arginine (5 g) was injected i.v. under fasting conditions (plasma glucose 4.8+/-0.1 mmol/l) and after raising blood glucose concentrations to 14.8+/-0.1 and 29.8+/-0.2 mmol/l. The acute glucagon response (AGR) to arginine during the three glucose levels (AGR(1), AGR(2), AGR(3)) was estimated, as was the suppression of baseline glucagon by the increased glucose. All women also underwent a 2-h euglycaemic-hyperinsulinaemic clamp study for estimation of insulin sensitivity. RESULTS Insulin sensitivity was normally distributed, with a mean of 73.2+/-29.3 (SD) nmol glucose kg(-1) min(-1)/pmol insulin l(-1). When relating the variables obtained from the arginine test to insulin sensitivity, insulin resistance was associated with increased AGR and with increased suppression of glucagon levels by glucose. For example, the regression between insulin sensitivity and AGR(2) was r=-0.38 (p<0.001) and between insulin sensitivity and suppression of glucagon levels by 14.8 mmol/l glucose r=0.36 (p<0.001). Insulin sensitivity also correlated negatively with insulin secretion; multivariate analysis revealed that changes in insulin sensitivity and insulin secretion were independently related to changes in glucagon secretion. CONCLUSIONS/INTERPRETATION The body adapts to insulin resistance by increasing the glucagon response to arginine and by increasing the suppression of glucagon levels by glucose. Hence, not only the islet beta cells but also the alpha cells seem to undergo compensatory changes during the development of insulin resistance.
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Affiliation(s)
- B Ahrén
- Department of Medicine, Lund University, B11 BMC, SE-221 84 LUND, Sweden.
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Vasudevan AR, Balasubramanyam A. Thiazolidinediones: a review of their mechanisms of insulin sensitization, therapeutic potential, clinical efficacy, and tolerability. Diabetes Technol Ther 2004; 6:850-63. [PMID: 15684639 DOI: 10.1089/dia.2004.6.850] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The thiazolidinediones (TZDs) rosiglitazone and pioglitazone are newer additions to the antidiabetic armamentarium and are indicated for the treatment of type 2 diabetes mellitus (T2DM) in the United States. The TZDs are peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists that provide clinically effective glycemic control and unique pharmacologic effects on multiple risk factors for T2DM-related morbidity, including improvement of insulin sensitivity and endothelial dysfunction, reduction of blood pressure, and amelioration of dyslipidemia. Weight gain and fluid retention occur with TZD therapy, especially when they are administered in higher doses and in combination with insulin. Although fluid retention associated with the use of TZDs is generally mild and reversible, these agents should not be used in patients with New York Heart Association Class III or IV heart failure symptoms. The findings of ongoing, long-term, prospective studies will clarify the role of the TZDs in the treatment of T2DM, particularly in terms of the durability of improvements in glycemic control, insulin sensitivity, pancreatic beta- cell function, and cardiovascular health.
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Affiliation(s)
- Abu R Vasudevan
- Division of Diabetes, Endocrinology, and Metabolism, Baylor College of Medicine, Houston, Texas 77030, USA
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Durbin RJ. Thiazolidinedione therapy in the prevention/delay of type 2 diabetes in patients with impaired glucose tolerance and insulin resistance. Diabetes Obes Metab 2004; 6:280-5. [PMID: 15171752 DOI: 10.1111/j.1462-8902.2004.0348.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIM The second-generation thiazolidinediones (TZDs), rosiglitazone and pioglitazone, significantly decrease fasting plasma glucose and glycosylated haemoglobin (HbA(1c)) levels in patients with diabetes. Recent studies suggest that early treatment with TZDs may prevent the progression from insulin resistance (IR) to type 2 diabetes mellitus (T2DM). This prospective analysis examined the effect of early TZD treatment in the prevention or delay of T2DM in a multiethnic population with impaired glucose tolerance (IGT) and IR. METHODS The analysis included 172 patients (aged 29-86 years) with IGT and IR (normal or borderline HbA(1c), C-peptide levels > 2 mg/ml, fasting blood sugar 100-125 mg/dl, and 2-h postprandial blood glucose levels 140-200 mg/dl). Patients in the active treatment group (n = 101) had received troglitazone for an average of 10 months before being randomly switched to rosiglitazone (4 mg/day) or pioglitazone (30 mg/day). Patients were switched when troglitazone was withdrawn from the US market because of liver toxicity concerns. Patients with IGT and IR who received no antidiabetic medication served as a control group (n = 71). HbA(1c) and C-peptide levels were measured at baseline (2 years) and study end point (3 years). Kaplan-Meier testing, using time to outcome as the main outcome variable, determined risk reduction in the TZD group relative to the control group. RESULTS Mean HbA(1c) and C-peptide levels decreased for patients receiving either TZD at the 2-year assessment, and reductions were maintained at study end point. After 2 years, none of the patients receiving TZD therapy progressed to T2DM; three patients progressed to T2DM by study end point. In the control group, 11 patients became diabetic after 2 years and 19 patients became diabetic by the end of the study. The incidence (risk reduction) of diabetes after 3 years was 88.9% lower in the TZD group compared with the control group (p < 0.001). CONCLUSIONS The TZDs, rosiglitazone and pioglitazone, were effective in reducing HbA(1c) and C-peptide levels in patients with IGT/IR. Progression of IR/IGT to T2DM appears to be significantly delayed or prevented with early TZD treatment.
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Affiliation(s)
- R J Durbin
- South Federal Family Practice, Denver, CO 80219, USA.
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