Fan Hong-Qi, Gu Nan, Liu Feng, Fei Li, Pan Xiao-Qin, Guo Mei, Chen Rong-Hua, Guo Xi-Rong
Department of Pediatrics, Nanjing Maternal and Child Health Hospital of Nanjing Medical University, Nanjing 210004, China.
Acta Pharmacol Sin. 2007 Mar;28(3):410-6. doi: 10.1111/j.1745-7254.2007.00523.x.
To assess the effects and mechanisms of the action of resistin on basal and insulin-stimulated glucose uptake in rat skeletal muscle cells.
Rat myoblasts (L6) were cultured and differentiated into myotubes followed by stimulation with single commercial resistin (130 ng/mL, 0-24 h) or cultured supernatant from 293-T cells transfected with resistin-expressing vectors (130 ng/mL, 0-24 h). Liquid scintillation counting was used to quantitate [3H] 2-deoxyglucose uptake. The translocation of insulin-sensitive glucose transporters GLUT4 and GLUT1, synaptosomal-associated protein 23 (SNAP23) and GLUT protein content, as well as the tyrosine phosphorylation status and protein content of insulin receptor substrate (IRS)-1, were assessed by Western blotting.
Treatment of L6 myotubes with single resistin or cultured supernatant containing recombinant resistin reduced basal and insulin-stimulated 2-deoxyglucose uptake and impaired insulin-stimulated GLUT4 translocation. While SNAP23 protein content was decreased, no effects were noted in GLUT4 or GLUT1 protein content. Resistin also diminished insulin-stimulated IRS-1 tyrosine phosphorylation levels without affecting its protein content. The effects of recombinant resistin from 293-T cells transfected with resistin-expressing vectors were greater than that of single resistin treatment.
Resistin regulated IRS-1 function and decreased GLUT4 translocation and glucose uptake in response to insulin. The downregulated expression of SNAP23 may have been partly attributed to the decrease of glucose uptake by resistin treatment. These observations highlight the potential role of resistin in the pathophysiology of type 2 diabetes related to obesity.
评估抵抗素对大鼠骨骼肌细胞基础葡萄糖摄取及胰岛素刺激的葡萄糖摄取的作用及其机制。
培养大鼠成肌细胞(L6)并使其分化为肌管,随后用单一商业抵抗素(130 ng/mL,0 - 24小时)或用转染了抵抗素表达载体的293 - T细胞的培养上清液(130 ng/mL,0 - 24小时)进行刺激。采用液体闪烁计数法定量测定[3H]2 - 脱氧葡萄糖摄取。通过蛋白质印迹法评估胰岛素敏感性葡萄糖转运蛋白GLUT4和GLUT1、突触小体相关蛋白23(SNAP23)的转位以及GLUT蛋白含量,以及胰岛素受体底物(IRS)-1的酪氨酸磷酸化状态和蛋白含量。
用单一抵抗素或含重组抵抗素的培养上清液处理L6肌管,可降低基础葡萄糖摄取及胰岛素刺激的2 - 脱氧葡萄糖摄取,并损害胰岛素刺激的GLUT4转位。虽然SNAP23蛋白含量降低,但GLUT4或GLUT1蛋白含量未受影响。抵抗素还降低了胰岛素刺激的IRS - 1酪氨酸磷酸化水平,但不影响其蛋白含量。转染了抵抗素表达载体的293 - T细胞产生的重组抵抗素的作用大于单一抵抗素处理。
抵抗素调节IRS - 1功能,降低胰岛素刺激的GLUT4转位和葡萄糖摄取。SNAP23表达下调可能部分归因于抵抗素处理导致的葡萄糖摄取减少。这些观察结果突出了抵抗素在与肥胖相关的2型糖尿病病理生理学中的潜在作用。