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目的研究Ghrelin对L6大鼠成肌细胞在棕榈酸诱导下的葡萄糖代谢和胰岛素敏感性的影响,并探讨其可能的机理。方法培养L6大鼠成肌细胞,诱导分化后利用0.3 mmol/L的棕榈酸作用16 h,实验组加入不同剂量的Ghrelin(1、10和100 nmol/L)作用8 h,采用葡萄糖氧化酶-过氧化物酶法(GOD-POD)检测骨骼肌细胞对葡萄糖的摄取,并在荧光共聚焦显微镜下观察细胞膜葡萄糖转运因子-4(GLUT-4)蛋白染色;采用免疫印迹(Western blot)法检测骨骼肌细胞中总蛋白激酶B(Akt)、磷酸化蛋白激酶B(pAkt)、总糖原合成酶激酶-3β(GSK-3β)和磷酸化糖原合成酶激酶-3β(pGSK-3β)蛋白的表达。结果 Ghrelin使胰岛素抵抗之L6大鼠成肌细胞葡萄糖摄取量增加,细胞膜GLUT-4染色加深,pAkt及pGSK-3β蛋白表达增加(磷酸化表达增加),而总Akt和总GSK-3β蛋白无明显变化,这种作用可被PI3K阻断剂(LY294002)消除。结论 Ghrelin通过磷酯酰肌醇-3激酶/蛋白激酶B/糖原合成酶激酶-3β(PI3K/Akt/GSK-3β)信号途径促进L6大鼠成肌细胞葡萄糖摄取量,从而提高L6大鼠成肌细胞胰岛素的敏感性。
Objective To investigate the effect of Ghrelin on glucose metabolism and insulin sensitivity induced by palmitate in L6 rat myoblasts and to explore its possible mechanism. Methods L6 rat myoblasts were induced to differentiate and then treated with 0.3 mmol / L palmitic acid for 16 h. Different concentrations of Ghrelin (1, 10 and 100 nmol / L) were added into the experimental group for 8 h. Glucose oxidase - Peroxidase (GOD-POD) was used to detect the uptake of glucose by skeletal muscle cells. The expression of glucose transporter-4 (GLUT-4) protein was observed under fluorescent confocal microscopy. Western blot Total protein kinase B (Akt), phospho-protein kinase B (pAkt), total glycogen synthase kinase-3beta (GSK-3beta) and phosphosycogen synthase kinase- 3beta (pGSK-3beta) proteins in skeletal muscle cells expression. Results Ghrelin increased the glucose uptake in the myoblasts of insulin-resistant L6 rats. The GLUT-4 staining of the cell membrane was deepened, the expression of pAkt and pGSK-3β increased (phosphorylation was increased), while the total Akt and total GSK-3β protein were not significantly Change, this effect can be PI3K blocker (LY294002) to eliminate. Conclusions Ghrelin enhances the glucose uptake in L6 myoblasts via the PI3K / Akt / GSK-3β signaling pathway, thereby increasing the L6 rat Myoblast insulin sensitivity.