Disordered branched chain amino acid catabolism in pancreatic islets is associated with postprandial hypersecretion of glucagon in diabetic mice.

Autor: Wada E; Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan., Kobayashi M; Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan., Kohno D; Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan., Kikuchi O; Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan., Suga T; Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan., Matsui S; Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan; Laboratory of Nutrition Chemistry, Division of Food Science and Biotechnology Graduate School of Agriculture, Kyoto University, Kyoto, Japan., Yokota-Hashimoto H; Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan., Honzawa N; Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan., Ikeuchi Y; Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan., Tsuneoka H; Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan., Hirano T; Education and Research Support Center, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan., Obinata H; Education and Research Support Center, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan., Sasaki T; Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan; Laboratory of Nutrition Chemistry, Division of Food Science and Biotechnology Graduate School of Agriculture, Kyoto University, Kyoto, Japan., Kitamura T; Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan. Electronic address: kitamura@gunma-u.ac.jp.
Jazyk: angličtina
Zdroj: The Journal of nutritional biochemistry [J Nutr Biochem] 2021 Nov; Vol. 97, pp. 108811. Date of Electronic Publication: 2021 Jun 28.
DOI: 10.1016/j.jnutbio.2021.108811
Abstrakt: Dysregulation of glucagon is associated with the pathophysiology of type 2 diabetes. We previously reported that postprandial hyperglucagonemia is more obvious than fasting hyperglucagonemia in type 2 diabetes patients. However, which nutrient stimulates glucagon secretion in the diabetic state and the underlying mechanism after nutrient intake are unclear. To answer these questions, we measured plasma glucagon levels in diabetic mice after oral administration of various nutrients. The effects of nutrients on glucagon secretion were assessed using islets isolated from diabetic mice and palmitate-treated islets. In addition, we analyzed the expression levels of branched chain amino acid (BCAA) catabolism-related enzymes and their metabolites in diabetic islets. We found that protein, but not carbohydrate or lipid, increased plasma glucagon levels in diabetic mice. Among amino acids, BCAAs, but not the other essential or nonessential amino acids, increased plasma glucagon levels. BCAAs also directly increased the intracellular calcium concentration in α cells. When BCAAs transport was suppressed by an inhibitor of system L-amino acid transporters, glucagon secretion was reduced even in the presence of BCAAs. We also found that the expression levels of BCAA catabolism-related enzymes and their metabolite contents were altered in diabetic islets and palmitate-treated islets compared to control islets, indicating disordered BCAA catabolism in diabetic islets. Furthermore, BCKDK inhibitor BT2 suppressed BCAA-induced hypersecretion of glucagon in diabetic islets and palmitate-treated islets. Taken together, postprandial hypersecretion of glucagon in the diabetic state is attributable to disordered BCAA catabolism in pancreatic islet cells.
(Copyright © 2021. Published by Elsevier Inc.)
Databáze: MEDLINE
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