Department of Structural Biology, Molecular and Genetic, State University of Ponta Grossa, Ponta Grossa, PR, Brazil.
Acta Physiol (Oxf). 2013 Sep;209(1):34-44. doi: 10.1111/apha.12128. Epub 2013 Jul 1.
Glucagon-like peptide-1 (GLP-1) is an important modulator of insulin secretion by endocrine pancreas. In the present study, we investigated the effect of swim training on GLP-1 insulinotropic action in pancreatic islets from monosodium glutamate (MSG)-obese rats.
Obesity was induced by neonatal MSG administration. MSG-obese and control (CON) exercised rats swam for 30 min (3 times week(-1) ) for 10 weeks. Pancreatic islets were isolated by colagenase technique and incubated with low (5.6 mM) or high (16.7 mM) glucose concentrations in the presence or absence of GLP-1 (10 nM). In addition, GLP-1 gene expression in ileum was quantified in fasting and glucose conditions.
Exercise reduced obesity and hyperinsulinemia in MSG-obese rats. Swim training also inhibited glucose-induced insulin secretion in islets from both groups. Islets from MSG-obese rats maintained GLP-1 insulinotropic response in low glucose concentration. In contrast, in the presence of high glucose concentration, GLP-1 insulinotropic action was absent in islets from MSG-obese rats. Islets from MSG-exercised rats showed reduced GLP-1 insulinotropic action in the presence of low glucose. However, in high glucose concentration swim training restored GLP-1 insulinotropic response in islets from MSG-obese rats. In all groups, glucose intake increased GLP-1 immunoreactivity and gene expression in ileum cells in relation to fasting conditions. Swim training reduced these parameters only in ileum cells from CON-exercised rats. Neither MSG treatment nor exercise affected GLP-1 expression in the ileum.
Exercise avoids insulin hypersecretion restoring GLP-1's insulinotropic action in pancreatic islets from MSG-obese rats.
胰高血糖素样肽-1（GLP-1）是内分泌胰腺胰岛素分泌的重要调节剂。本研究旨在探讨游泳训练对谷氨酸钠（MSG）肥胖大鼠胰岛 GLP-1 促胰岛素作用的影响。
通过新生鼠 MSG 给药诱导肥胖。MSG 肥胖和对照（CON）运动大鼠游泳 30 分钟（每周 3 次）10 周。用胶原酶技术分离胰岛，并在存在或不存在 GLP-1（10 nM）的情况下，用低（5.6 mM）或高（16.7 mM）葡萄糖浓度孵育胰岛。此外，在空腹和葡萄糖条件下定量测定回肠中的 GLP-1 基因表达。
运动降低了 MSG 肥胖大鼠的肥胖和高胰岛素血症。游泳训练还抑制了两组胰岛的葡萄糖诱导胰岛素分泌。在低葡萄糖浓度下，MSG 肥胖大鼠胰岛仍保持 GLP-1 促胰岛素反应。相比之下，在高葡萄糖浓度下，MSG 肥胖大鼠胰岛中缺乏 GLP-1 促胰岛素作用。在低葡萄糖浓度下，MSG 运动大鼠的胰岛显示 GLP-1 促胰岛素作用降低。然而，在高葡萄糖浓度下，游泳训练恢复了 MSG 肥胖大鼠胰岛的 GLP-1 促胰岛素反应。在所有组中，与空腹条件相比，葡萄糖摄入增加了回肠细胞中的 GLP-1 免疫反应和基因表达。游泳训练仅降低了 CON 运动大鼠回肠细胞中的这些参数。MSG 处理或运动均未影响回肠中的 GLP-1 表达。
运动可避免胰岛素分泌过多，恢复 MSG 肥胖大鼠胰岛中 GLP-1 的促胰岛素作用。
