Inhibition of the action of nonsuppressible insulin-like activity on isolated rat fat cells by binding to its carrier protein.
Inhibition of the action of nonsuppressible insulin-like activity on isolated rat fat cells by binding to its carrier protein.
复制标题
通过与其载体蛋白结合，抑制不可抑制的胰岛素样活性对分离的大鼠脂肪细胞的作用。
DOI：
--
复制
发表时间：
1979
影响因子：
15.9
通讯作者：
E. Froesch
中科院分区：
文献类型：
--
作者：
J. Zapf;E. Schoenle;G. Jagars;I. Sand;J. Grunwald;E. Froesch
从人血清中提取和纯化的不可抑制的胰岛素样活性 (NSILA-S) 在体外模拟所有胰岛素样作用，并且在注射后在存在过量胰岛素抗体的情况下在体内模拟所有胰岛素样作用。然而，没有证据表明它以其天然形式在循环中发挥急性胰岛素样作用，在循环中它几乎完全与特定的大分子量载体蛋白结合。在本文中，我们表明，部分纯化的 NSILA-S 载体蛋白缺乏内源性胰岛素样活性，可抑制 NSILA-S（而非胰岛素）对分离大鼠脂肪细胞中 3-0-甲基葡萄糖转运和 [U-(14)C] 葡萄糖脂肪生成的刺激作用。同时，它可以防止 (125)I 标记的 NSILA-S 与胰岛素受体和 NSILA-S 结合位点的结合。因此，对于天然 NSILA-S 在体内不存在急性胰岛素样作用，提供以下解释： 在天然血清中，NSILA-S 几乎完全作为 NSILA-S-载体复合物出现。根据最近的发现，这种复合物通过毛细血管的通道受到限制。此外，目前的结果表明，它是代谢不活跃的，或者至少具有降低的代谢活性。然而，众所周知的现象是，全血清在体外对脂肪组织产生显着的不可抑制的胰岛素样作用，这似乎主要是由与 NSILA-S 载体复合物不同的大分子量胰岛素样蛋白的存在引起的。
Nonsuppressible insulin-like activity extracted and purified from human serum (NSILA-S) mimics all insulin-like effects in vitro and, after injection, in vivo in the presence of excess insulin antibodies. However, there is no evidence that it exerts acute insulin-like effects in its native form in the circulation, where it is almost completely bound to a specific large molecular weight carrier protein. In this paper we show that partially purified NSILA-S-carrier protein, devoid of endogenous insulin-like activity, inhibits the stimulatory effect of NSILA-S, but not of insulin, on 3-0-methylglucose transport and on lipogenesis from [U-(14)C]glucose in isolated rat fat cells. Concomitantly, it prevents binding of (125)I-labeled NSILA-S to the insulin receptor and to the NSILA-S-binding site. The following explanation is, therefore, offered for the absence of acute insulin-like effects of native NSILA-S in vivo: In native serum NSILA-S occurs almost exclusively as NSILA-S-carrier complex. According to recent findings the passage of this complex through blood capillaries is restricted. The present results indicate that, in addition, it is metabolically inactive, or, at least, possesses reduced metabolic activity. The well-known phenomenon that whole serum, nevertheless, exerts pronounced nonsuppressible insulin-like effects on adipose tissue in vitro seems, therefore, to be mainly caused by the presence of a large molecular weight insulin-like protein not identical to the NSILA-S-carrier complex.