Reed M J, Reaven G M, Mondon C E, Azhar S
Department of Medicine, Stanford University School of Medicine, California.
J Gerontol. 1993 Jul;48(4):B139-44. doi: 10.1093/geronj/48.4.b139.
We compared skeletal muscle glucose uptake between young and mature rats. Hindlimb perfusions at insulin concentrations of 0, 100, 250, or 10,000 microU/mL were performed on male Sprague-Dawley rats at 5 weeks or 4 months of age. Basal glucose uptake, and glucose uptake at all insulin concentrations were significantly lower in the 4-month-old mature rats (p < .05). This difference was most pronounced at maximally stimulating insulin concentrations. Skeletal muscle insulin receptor binding, autophosphorylation, and tyrosine kinase activity did not differ between young and mature rats. Surprisingly, GLUT-4 glucose transporter content was significantly higher in several muscles of the mature rats (p < .05). Therefore, the decline in insulin-stimulated glucose uptake in hindlimbs of mature rats cannot be explained by decreased activity of these steps in the glucose transport system.
我们比较了幼年和成年大鼠骨骼肌对葡萄糖的摄取情况。对5周龄或4月龄的雄性斯普拉格-道利大鼠进行胰岛素浓度为0、100、250或10000微单位/毫升的后肢灌注。4月龄成年大鼠的基础葡萄糖摄取以及所有胰岛素浓度下的葡萄糖摄取均显著降低（p < 0.05）。这种差异在最大刺激胰岛素浓度时最为明显。幼年和成年大鼠之间骨骼肌胰岛素受体结合、自身磷酸化及酪氨酸激酶活性并无差异。令人惊讶的是，成年大鼠几块肌肉中的GLUT-4葡萄糖转运体含量显著更高（p < 0.05）。因此，成年大鼠后肢胰岛素刺激的葡萄糖摄取下降不能用葡萄糖转运系统中这些步骤的活性降低来解释。
