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Xu SY, Zhang Z, Liu CY, Guo QY, Lu B, Gu P, Shao JQ. Association between time in range, a novel measurement of glycemic control and islet secretory function in chinese patients with type 2 diabetes mellitus-An observational study. Diabetes Res Clin Pract 2021; 173:108684. [PMID: 33539867 DOI: 10.1016/j.diabres.2021.108684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 01/15/2021] [Accepted: 01/20/2021] [Indexed: 10/22/2022]
Abstract
AIMS To explore the association between dynamic islet secretory function and TIR (time in range), a new valuable metric of glycemic control in type 2 diabetes (T2D). METHODS In this observational study 256 patients with type 2 diabetes were included and continuous glucose monitoring system (CGMS) were applied to monitor blood glucose and also the calculation of TIR [the time spent in an individual's target glucose range (usually 3.9-10 mmol/L)]. The participants were divided into 3 groups according to the tertiles of TIR, 85 cases with TIR ≥ 65.05% (T1 group), 86 cases with 41.84 < TIR ≤ 65.05% (T2 group) and 85 cases with TIR < 41.84% (T3 group). Serum glucagon (GLA0h, GLA0.5h, GLA1h, GLA2h, GLA3h), C-peptide (Cp0h, Cp0.5h, Cp1h, Cp2h, Cp3h) concentration at different time points were measured after a 100 g standard steamed buns meal test to assess the pancreatic alpha cell and beta cell function. Spearman correlation analysis and multivariate linear stepwise regression analysis were adopted for statistical analysis. RESULTS The average age and diabetes duration of all the participants were separately 56.09 ± 13.8 years and 8.0 (4.0,15.0) years. Compared with patients in T1 group, participants in group T2 and T3 tend to have a lower concentration of C-peptide at all time points, as well as GLA0h, GLA2h and GLA3h (p < 0.05). TIR was positively correlated with C-peptide at different time points, area under the curve of C-peptide in half an hour (AUCCp0.5h), GLA0h, GLA3h, area under the curve of glucagon in half an hour (AUCGLA0.5h)(rs = 0.263, 0.414, 0.510, 0.587, 0.528, 0.360, 0.259, 0.144 and 0.208, respectively, p < 0.05) and was negatively correlated with the increment of serum glucagon from baseline at 0.5 h, 1 h and 2 h after the standard energy loaded(△GLA0.5h, △GLA1h, △GLA2h)(rs = -0.152,-0.172 and -0.203, respectively, p < 0.05). Cp2h, Cp0h and GLA0h were independent factors for TIR (β = 6.558,-6.930, 0.247, respectively, p < 0.01). CONCLUSION Both islet alpha cell and beta cell secretory function have important influence on TIR, a novel vital index of glycemic fluctuation.
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Affiliation(s)
- Shao-Ying Xu
- Department of Endocrinology, Jinling Hospital, Southeast University, School of Medicine, Nanjing, Jiangsu, China.
| | - Zhen Zhang
- Department of Endocrinology, Jinling Hospital, Nanjing School of Clinical Medicine, Southern Medical University, Nanjing, Jiangsu, China.
| | - Chun-Yan Liu
- Affiliated Hospital of Jiangnan University, Nanjing, Jiangsu, China.
| | - Qing-Yu Guo
- Department of Endocrinology, Jinling Hospital, Nanjing University, School of Medicine, Nanjing, Jiangsu, China.
| | - Bin Lu
- Department of Endocrinology, Jinling Hospital, Nanjing University, Nanjing, Jiangsu, China.
| | - Ping Gu
- Department of Endocrinology, Jinling Hospital, Southeast University, School of Medicine, Nanjing, Jiangsu, China.
| | - Jia-Qing Shao
- Department of Endocrinology, Jinling Hospital, Southeast University, School of Medicine, Nanjing, Jiangsu, China.
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Guo K, Tian Q, Yang L, Zhou Z. The Role of Glucagon in Glycemic Variability in Type 1 Diabetes: A Narrative Review. Diabetes Metab Syndr Obes 2021; 14:4865-4873. [PMID: 34992395 PMCID: PMC8710064 DOI: 10.2147/dmso.s343514] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 12/01/2021] [Indexed: 01/20/2023] Open
Abstract
Type 1 diabetes mellitus (T1DM) is a progressive disease as a result of the severe destruction of islet β-cell function, which leads to high glucose variability in patients. However, α-cell function is also compromised in patients with T1DM, characterized by aberrant fasting and postprandial glucagon secretion. According to recent studies, this aberrant glucagon secretion plays an increasing role in hyperglycemia, insulin-induced hypoglycemia and exercise-associated hypoglycemia in patients with T1DM. With application of continuous glucose monitoring system, dozens of metrics enable the assessment of glycemic variability, which is an integral component of glycemic control for patients with T1DM. There is growing evidences to illustrate the contribution of glucagon secretion to the glycemic variability in patients with T1DM, which may promote the development of new treatment strategies aiming to mitigate glycemic variability associated with aberrant glucagon secretion.
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Affiliation(s)
- Keyu Guo
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, 410011, Hunan, People’s Republic of China
| | - Qi Tian
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, 410011, Hunan, People’s Republic of China
| | - Lin Yang
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, 410011, Hunan, People’s Republic of China
- Correspondence: Lin Yang; Zhiguang Zhou Email ;
| | - Zhiguang Zhou
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, 410011, Hunan, People’s Republic of China
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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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Takahashi N, Chujo D, Kajio H, Ueki K. Contribution of pancreatic α-cell function to insulin sensitivity and glycemic variability in patients with type 1 diabetes. J Diabetes Investig 2019; 10:690-698. [PMID: 30290079 PMCID: PMC6497601 DOI: 10.1111/jdi.12949] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Revised: 09/18/2018] [Accepted: 09/30/2018] [Indexed: 12/25/2022] Open
Abstract
AIMS/INTRODUCTION To evaluate the contribution of pancreatic α-cell function to the dawn phenomenon, insulin sensitivity, hepatic glucose uptake and glycemic variability in patients with type 1 diabetes. MATERIALS AND METHODS In 40 patients with type 1 diabetes, arginine stimulation tests were carried out, and the area under the curve (AUC) of glucagon was measured using radioimmunoassays (AUCglc RIA ) and enzyme-linked immunosorbent assays (AUCglc ELISA ). The ratio of the insulin dose delivered by an artificial pancreas to maintain euglycemia between 04.00 and 08.00 hours or between 00.00 and 04.00 hours was measured as the dawn index. The glucose infusion rate and hepatic glucose uptake were measured using hyperinsulinemic euglycemic clamp and clamp oral glucose loading tests. Glycemic variability in 96 h was measured by continuous glucose monitoring. RESULTS The median dawn index (1.7, interquartile range 1.0-2.8) was not correlated with AUCglc RIA (R2 = 0.03, P = 0.39) or AUCglc ELISA (R2 = 0.04, P = 0.32). The median glucose infusion rate (7.3 mg/kg/min, interquartile range 6.4-9.2 mg/kg/min) was significantly correlated with AUCglc RIA (R2 = 0.20, P = 0.02) and AUCglc ELISA (R2 = 0.21, P = 0.02). The median hepatic glucose uptake (65.3%, interquartile range 40.0-87.3%) was not correlated with AUCglc RIA (R2 = 0.07, P = 0.26) or AUCglc ELISA (R2 = 0.26, P = 0.79). The standard deviation of glucose levels measured by continuous glucose monitoring was significantly correlated with AUCglc RIA (R2 = 0.11, P = 0.049), but not with AUCglc ELISA (R2 = 0.01, P = 0.75). CONCLUSIONS Pancreatic α-cell function contributed to insulin sensitivity in patients with type 1 diabetes.
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Affiliation(s)
- Nobuyuki Takahashi
- Department of Diabetes, Endocrinology, and MetabolismCenter HospitalNational Center for Global Health and MedicineTokyoJapan
- Department of Molecular DiabetologyGraduate School of MedicineThe University of TokyoTokyoJapan
| | - Daisuke Chujo
- Department of Diabetes, Endocrinology, and MetabolismCenter HospitalNational Center for Global Health and MedicineTokyoJapan
| | - Hiroshi Kajio
- Department of Diabetes, Endocrinology, and MetabolismCenter HospitalNational Center for Global Health and MedicineTokyoJapan
| | - Kohjiro Ueki
- Department of Diabetes, Endocrinology, and MetabolismCenter HospitalNational Center for Global Health and MedicineTokyoJapan
- Department of Molecular DiabetologyGraduate School of MedicineThe University of TokyoTokyoJapan
- Diabetes Research CenterResearch InstituteNational Center for Global Health and MedicineTokyoJapan
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Murase-Mishiba Y, Bessho-Tachibana M, Imagawa A. "Preserved" glucagon secretion in fulminant type 1 diabetes. J Diabetes Investig 2018; 10:186-187. [PMID: 30411869 PMCID: PMC6319491 DOI: 10.1111/jdi.12946] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 09/25/2018] [Accepted: 09/28/2018] [Indexed: 12/26/2022] Open
Abstract
Mixed‐meal tolerance tests were carried out after an overnight fast. Healthy control participants (■), type 1A diabetespatients (○) and fulminant type 1 diabetic patients (▲). Data are presented as the mean ± standard error of the mean.
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Affiliation(s)
- Yuko Murase-Mishiba
- Department of Internal Medicine (I), Osaka Medical College, Takatsuki, Osaka, Japan
| | | | - Akihisa Imagawa
- Department of Internal Medicine (I), Osaka Medical College, Takatsuki, Osaka, Japan
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Taurine improves glucose tolerance in STZ-induced insulin-deficient diabetic mice. Diabetol Int 2018; 9:234-242. [PMID: 30603373 DOI: 10.1007/s13340-018-0353-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 03/13/2018] [Indexed: 12/11/2022]
Abstract
Blood glucose levels fluctuate considerably in diabetic patients with reduced secretion of endogenous insulin. We previously reported that glucagon is secreted excessively in these patients and that taurine increases glucagon secretion in vitro. Therefore, we hypothesized that glucose tolerance would further deteriorate when taurine was administered to diabetic mice incapable of insulin secretion. We generated four groups of streptozotocin (STZ)-treated C57BL/6J mice (STZ-mice): STZ-mice without taurine treatment (STZ-Con), STZ-mice treated with 0.5% (w/v) taurine (STZ-0.5% Tau), STZ-mice treated with 1% (w/v) taurine (STZ-1% Tau), and STZ-mice treated with 2% (w/v) taurine (STZ-2% Tau). Mice were treated for 4 weeks, and then, we evaluated glucose tolerance, pancreatic β-cell area and α-cell area, pancreatic insulin and glucagon content, and daily blood glucose variability. As a result, following the administration of taurine, glucose tolerance improved, both pancreatic β- and α-cell area increased, and both insulin and glucagon content increased. In the 1% taurine administration group, blood glucose variability decreased. These unexpected results suggest that taurine improves glucose tolerance, in spite of its subsequent increased glucagon production, partly by increasing pancreatic β-cells and insulin production in vivo.
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Wang X, Yang J, Chang B, Shan C, Xu Y, Zheng M, Wang Y, Ren H, Chen L. Glucagon secretion is increased in patients with Type 2 diabetic nephropathy. J Diabetes Complications 2016; 30:488-93. [PMID: 26908298 DOI: 10.1016/j.jdiacomp.2015.12.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/03/2015] [Accepted: 12/22/2015] [Indexed: 02/06/2023]
Abstract
AIMS Currently little is known about the relationship between renal function, albuminuria and glucagon; we analyzed the secretion of glucagon (GLA) and C-peptide in Type 2 diabetic patients with different degrees of nephropathy. METHODS 357 patients with Type 2 diabetes including 119 cases without nephropathy and 238 cases with nephropathy were divided into four groups according to the stages of diabetic nephropathy. Patients with diabetic nephropathy were further classified according to the level of estimated glomerular filtration rate (eGFR). OGTT and insulin, C-peptide, glucagon releasing tests were performed in all patients. Characteristics of glucagon and C-peptide secretion in different groups were compared. Glucagon/glucose ratio (GLA/GLU) and glucagon/insulin ratio (GLA/INS) were used to represent the inhibition of glucose or insulin on glucagon secretion, respectively. RESULTS With the progress of diabetic nephropathy, glucagon level increased significantly; the glucagon peak after glucose load delayed from 60 min to 120 min, whereas C-peptide level decreased significantly. Related factors analysis suggested that glucagon was independently correlated with eGFR. Further analysis showed that glucagon level was higher in group with eGFR<60 ml/min compared with that in group with eGFR≥60 ml/min. In addition, both GLA/INS and GLA/GLU were higher in group with eGFR<60 ml/min compared with those in group with eGFR≥60 ml/min. CONCLUSIONS Patients with Type 2 diabetic nephropathy have worsened islet alpha and beta cell function. Therefore medications based on the regulation of glucagon secretion may improve glycemic control and also be beneficial for delaying the progress of diabetic nephropathy.
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Affiliation(s)
- Xiaoyu Wang
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, 300070 Tianjin, China; Department of Endocrinology, Tianjin First Center Hospital, Tianjin 300192, China
| | - Juhong Yang
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, 300070 Tianjin, China
| | - Baocheng Chang
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, 300070 Tianjin, China
| | - Chunyan Shan
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, 300070 Tianjin, China
| | - Yanguang Xu
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, 300070 Tianjin, China
| | - Miaoyan Zheng
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, 300070 Tianjin, China
| | - Ying Wang
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, 300070 Tianjin, China
| | - Huizhu Ren
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, 300070 Tianjin, China
| | - Liming Chen
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, 300070 Tianjin, China.
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Osawa S, Yasuda T, Kaneto H, Shimo N, Yamamoto Y, Kawamori D, Miyatsuka T, Matsuoka TA, Shimomura I. Case of aniridia with a heterozygous PAX6 mutation in which the glucagon response to arginine was evaluated. J Diabetes Investig 2015; 6:105-6. [PMID: 25621140 PMCID: PMC4296710 DOI: 10.1111/jdi.12251] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 05/11/2014] [Accepted: 05/18/2014] [Indexed: 11/30/2022] Open
Affiliation(s)
- Saeko Osawa
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine Osaka, Japan
| | - Tetsuyuki Yasuda
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine Osaka, Japan
| | - Hideaki Kaneto
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine Osaka, Japan
| | - Naoki Shimo
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine Osaka, Japan
| | - Yuichi Yamamoto
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine Osaka, Japan
| | - Dan Kawamori
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine Osaka, Japan
| | - Takeshi Miyatsuka
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine Osaka, Japan
| | - Taka-Aki Matsuoka
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine Osaka, Japan
| | - Iichiro Shimomura
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine Osaka, Japan
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Bessho M, Murase-Mishiba Y, Imagawa A, Terasaki J, Hanafusa T. Possible contribution of taurine to distorted glucagon secretion in intra-islet insulin deficiency: a metabolome analysis using a novel α-cell model of insulin-deficient diabetes. PLoS One 2014; 9:e113254. [PMID: 25393115 PMCID: PMC4231115 DOI: 10.1371/journal.pone.0113254] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 10/24/2014] [Indexed: 01/30/2023] Open
Abstract
Glycemic instability is a serious problem in patients with insulin-deficient diabetes, and it may be due in part to abnormal endogenous glucagon secretion. However, the intracellular metabolic mechanism(s) involved in the aberrant glucagon response under the condition of insulin deficiency has not yet been elucidated. To investigate the metabolic traits that underlie the distortion of glucagon secretion under insulin deficient conditions, we generated an αTC1-6 cell line with stable knockdown of the insulin receptor (IRKD), i.e., an in vitro α-cell model for insulin-deficient diabetes, which exhibits an abnormal glucagon response to glucose. A comprehensive metabolomic analysis of the IRKD αTC1-6 cells (IRKD cells) revealed some candidate metabolites whose levels differed markedly compared to those in control αTC1-6 cells, but also which could affect the glucagon release in IRKD cells. Of these candidates, taurine was remarkably increased in the IRKD cells and was identified as a stimulator of glucagon in αTC1-6 cells. Taurine also paradoxically exaggerated the glucagon secretion at a high glucose concentration in IRKD cells and islets with IRKD. These results indicate that the metabolic alterations induced by IRKD in α-cells, especially the increase of taurine, may lead to the distorted glucagon response in IRKD cells, suggesting the importance of taurine in the paradoxical glucagon response and the resultant glucose instability in insulin-deficient diabetes.
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Affiliation(s)
- Megumi Bessho
- Department of Internal Medicine (I), Osaka Medical College, Osaka, Japan
| | | | - Akihisa Imagawa
- Department of Internal Medicine (I), Osaka Medical College, Osaka, Japan; Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Jungo Terasaki
- Department of Internal Medicine (I), Osaka Medical College, Osaka, Japan
| | - Toshiaki Hanafusa
- Department of Internal Medicine (I), Osaka Medical College, Osaka, Japan
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