Hiriart-Urdanivia Marcia, Sánchez-Soto Carmen, Velasco Myrian, Sabido-Barrera Jean, Ortiz-Huidobro Rosa Isela
Universidad Nacional Autónoma de México, Institute of Cell Physiology, Department of Cognitive Neuroscience, Mexico City, Mexico.
Gac Med Mex. 2019;155(5):500-503. doi: 10.24875/GMM.M20000339.
The metabolic syndrome describes a group of signs that increase the likelihood for developing type 2 diabetes mellitus, cardiovascular diseases and some types of cancer. The action of insulin depends on its binding to membrane receptors on its target cells. We wonder if blood insulin could travel bound to proteins and if, in the presence of hyperinsulinemia, a soluble insulin receptor might be generated. We used young adult Wistar rats (which have no predisposition to obesity or diabetes), whose drinking water was added 20 % of sugar and that were fed a standard diet ad libitum for two and six months. They were compared with control rats under the same conditions, but that had running water for consumption. At two months, the rats developed central obesity, moderate hypertension, high triglyceride levels, hyperinsulinemia, glucose intolerance and insulin resistance, i.e., metabolic syndrome. Electrophoresis of the rats' plasma proteins was performed, followed by Western Blot (WB) for insulin and for the outer portion of the insulin receptor. The bands corresponding to insulin and to the receptor external part were at the same molecular weight level, 25-fold higher than that of free insulin. We demonstrated that insulin, both in control animals and in those with hyperinsulinemia, travels bound to the receptor outer portion (ectodomain), which we called soluble insulin receptor, and that is released al higher amounts in response to plasma insulin increase; in rats with metabolic syndrome and hyperinsulinemia, plasma levels are much higher than in controls. Soluble insulin receptor increase in blood might be an early sign of metabolic syndrome.
代谢综合征描述的是一组会增加患2型糖尿病、心血管疾病和某些类型癌症可能性的体征。胰岛素的作用取决于其与靶细胞膜受体的结合。我们想知道血液中的胰岛素是否会与蛋白质结合运输，以及在高胰岛素血症的情况下，是否会产生可溶性胰岛素受体。我们使用了年轻的成年Wistar大鼠（它们没有肥胖或糖尿病的易感性），在其饮用水中添加20%的糖，并随意喂食标准饮食，持续两个月和六个月。将它们与在相同条件下但饮用自来水的对照大鼠进行比较。两个月时，这些大鼠出现了中心性肥胖、中度高血压、高甘油三酯水平、高胰岛素血症、葡萄糖不耐受和胰岛素抵抗，即代谢综合征。对大鼠血浆蛋白进行电泳，随后进行胰岛素和胰岛素受体外部部分的蛋白质免疫印迹（WB）分析。与胰岛素和受体外部部分相对应的条带处于相同的分子量水平，比游离胰岛素高25倍。我们证明，无论是对照动物还是患有高胰岛素血症的动物，胰岛素都与受体外部部分（胞外域）结合运输，我们将其称为可溶性胰岛素受体，并且随着血浆胰岛素水平的升高，其释放量会增加；在患有代谢综合征和高胰岛素血症的大鼠中，血浆水平比对照组高得多。血液中可溶性胰岛素受体的增加可能是代谢综合征的早期迹象。
