Insulin stimulates cellular iron uptake and causes the redistribution of intracellular transferrin receptors to the plasma membrane.
Insulin stimulates cellular iron uptake and causes the redistribution of intracellular transferrin receptors to the plasma membrane.
复制标题
DOI：
--
复制
发表时间：
1986-07
期刊：
影响因子：
--
通讯作者：
R. Davis;S. Corvera;M. Czech
中科院分区：
文献类型：
--
作者：
R. Davis;S. Corvera;M. Czech
胰岛素通过增加二铁转铁蛋白的摄取来刺激离体脂肪细胞的铁积累。二铁125 I-转铁蛋白的细胞表面结合的分析表明，胰岛素引起转铁蛋白受体的细胞表面数量增加3倍。该结果通过胰岛素增加抗大鼠转铁蛋白受体单克隆抗体（OX-26）与脂肪细胞表面的结合而得到证实。胰岛素这种作用的基础是通过研究从破裂的脂肪细胞中分离的膜组分中的转铁蛋白受体的数量来研究的。采用了两种方法。首先研究了双铁125 I-转铁蛋白与分离膜的结合等温线。其次，用去污剂溶解膜，并使用单克隆抗体OX-26通过免疫印迹法测量转铁蛋白受体的数量。据观察，胰岛素治疗的完整的脂肪细胞导致在数量的增加，转铁蛋白受体位于分离的质膜部分的破坏的脂肪细胞。此外，质膜转铁蛋白受体数量的增加与转铁蛋白受体数量的同时减少，在低密度微粒体部分先前显示由细胞内膜。转铁蛋白受体在细胞膜组分之间响应于胰岛素的这种重新分布与胰岛素对葡萄糖转运蛋白和II型胰岛素样生长因子受体的调节非常相似。我们得出结论，胰岛素刺激脂肪细胞铁的吸收的机制，可能涉及转铁蛋白受体的再分配从内部膜室（低密度微粒体）的细胞表面（质膜）。
Insulin stimulates the accumulation of iron by isolated fat cells by increasing the uptake of diferric transferrin. Analysis of the cell-surface binding of diferric 125I-transferrin indicated that insulin caused a 3-fold increase in the cell surface number of transferrin receptors. This result was confirmed by the demonstration that insulin increases the binding of an anti-rat transferrin receptor monoclonal antibody (OX-26) to the surface of fat cells. The basis of this effect of insulin was examined by investigating the number of transferrin receptors in membrane fractions isolated from disrupted fat cells. Two methods were employed. First the binding isotherm of diferric 125I-transferrin to the isolated membranes was studied. Second, the membranes were solubilized with detergent, and the number of transferrin receptors was measured by immunoblotting using the monoclonal antibody OX-26. It was observed that insulin treatment of intact fat cells resulted in an increase in the number of transferrin receptors located in the isolated plasma membrane fraction of the disrupted fat cells. Furthermore, the increase in the number of plasma membrane transferrin receptors was associated with a concomitant decrease in the transferrin receptor number in a low density microsome fraction previously shown to consist of intracellular membranes. This redistribution of transferrin receptors between cellular membrane fractions in response to insulin is remarkably similar to the regulation by insulin of glucose transporters and type II insulin-like growth factor receptors. We conclude that insulin stimulates fat cell iron uptake by a mechanism that may involve the redistribution of transferrin receptors from an internal membrane compartment (low density microsomes) to the cell surface (plasma membrane).