Identification of the insulin receptor of cerebral microvessels.
Identification of the insulin receptor of cerebral microvessels.
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脑微血管胰岛素受体的鉴定。
DOI：
10.1152/ajpendo.1985.248.1.e115
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Pillion,DJ
中科院分区：
文献类型：
--
作者：
Haskell,JF;Meezan,E;Pillion,DJ
众所周知，大脑微血管拥有胰岛素受体，最近被证明对这种激素的生理水平做出反应。对分离的脑微血管的结合数据的Scatchard分析给出了曲线图，并表明新生猪脑微血管每单位蛋白质的胰岛素受体数量比成年牛脑微血管多。新生猪和成年牛脑微血管胰岛素受体的高亲和力形式具有相似的结合常数(解离常数=0.3×10~(-9)M)。在新生猪和成年奶牛的制剂中，未标记胰岛素的存在加速了~(125)I-胰岛素从脑微血管的解离。用琥珀酸二异丁二胺酯将~(125)I-胰岛素与其受体在脑微血管内共价交联，并在十二烷基硫酸钠-聚丙烯酰胺凝胶上分离得到激素-受体复合体。在还原条件下，~(125)I-胰岛素与一个相对分子质量为130,000的多肽结合，与肝脏胰岛素受体的α-亚基没有区别。相比之下，非血管大脑皮质组织含有一种胰岛素受体，其阿尔法亚单位的相对分子质量低于从大脑皮质微血管中分离出来的胰岛素受体。
Cerebral microvessels are known to possess receptors for insulin and have recently been shown to respond to physiological levels of this hormone. Scatchard analysis of binding data obtained with isolated cerebral microvessels gave curvilinear plots and showed that neonatal porcine cerebral microvessels have a greater number of insulin receptors per unit of protein than adult bovine cerebral microvessels. The high-affinity form of the insulin receptors of both neonatal porcine and adult bovine cerebral microvessels have similar binding constants (dissociation constant = 0.3 X 10(-9) M). Dissociation of 125I-insulin from cerebral microvessels was accelerated by the presence of unlabeled insulin in preparations from both neonatal pigs and adult cows. 125I-insulin was covalently cross-linked to its receptor in cerebral microvessels with disuccinimidyl suberate, and the hormone-receptor complex was isolated on sodium dodecyl sulfate-polyacrylamide gels. Under reducing conditions, 125I-insulin was found associated with a polypeptide with a molecular weight of 130,000, which is indistinguishable from the alpha-subunit of the liver insulin receptor. In contrast, nonvascular cerebral cortical tissue contained an insulin receptor with an alpha-subunit that was lower in molecular weight than the form isolated from cerebral cortical microvessels.