Department of Physical Education, Chuzhou College, Chuzhou, Anhui Province 239012, PR China.
Gen Comp Endocrinol. 2011 Aug 1;173(1):159-63. doi: 10.1016/j.ygcen.2011.05.011. Epub 2011 May 31.
Seeing that galanin increases animal body weight on the conditions of inhibiting insulin secretion and animals with metabolic disorder of galanin easily suffer from diabetes, we postulate that endogenous galanin is necessary to reduce insulin resistance in adipocytes. To test this hypothesis, we compared four groups of rats to examine whether an increase in galanin secretion stimulated by swimming may reduce insulin resistance. The rats from sedentary and trained drug groups were injected by M35, a galanin antagonist. The rats from trained control and trained drug groups swam after each injection for four weeks. We found that exercise significantly elevated plasma galanin contents and glucose transporter 4 (GLUT4) mRNA levels in adipocytes. Meanwhile, M35 treatment reduced GLUT4 and GLUT4 mRNA levels, and glucose infusing rates in euglycemic-hyperinsulinemic clamp tests. The ratios of GLUT4 concentrations at plasma membranes to total cell membranes in both drug groups were lower compared with each control group, respectively. These observations suggest that endogenous galanin reduces insulin resistance by increasing GLUT4 contents and promoting GLUT4 transportation from intracellular membranes to plasma membranes in adipocytes. Galanin is an important hormone to reduce insulin resistance in rats.
鉴于甘丙肽在抑制胰岛素分泌的情况下会增加动物体重，且甘丙肽代谢紊乱的动物容易患糖尿病，我们推测内源性甘丙肽对于降低脂肪细胞的胰岛素抵抗是必需的。为了验证这一假说，我们比较了四组大鼠，以观察游泳刺激甘丙肽分泌增加是否可以减轻胰岛素抵抗。久坐不动和训练药物组的大鼠被注射了甘丙肽拮抗剂 M35。训练对照组和训练药物组的大鼠在每次注射后游泳四周。我们发现运动显著提高了血浆甘丙肽含量和脂肪细胞中的葡萄糖转运蛋白 4（GLUT4）mRNA 水平。同时，M35 处理降低了 GLUT4 和 GLUT4 mRNA 水平，以及在正常血糖高胰岛素钳夹试验中的葡萄糖输注率。与各自的对照组相比，两个药物组的质膜 GLUT4 浓度与总细胞膜的比值均较低。这些观察结果表明，内源性甘丙肽通过增加 GLUT4 含量并促进 GLUT4 从细胞内膜向质膜转运来减轻脂肪细胞的胰岛素抵抗。甘丙肽是降低大鼠胰岛素抵抗的重要激素。
