Watanabe N, Kobayashi M, Maegawa H, Ishibashi O, Takata Y, Shigeta Y
Diabetes Res Clin Pract. 1986 Apr;2(1):1-8. doi: 10.1016/s0168-8227(86)80022-5.
The long-term in vitro effects of insulin on insulin binding and glucose transport were studied using rat adipocytes in a time-dependent manner. Isolated fat cells were incubated with insulin (100 ng/ml) for 4, 8 and 24 h in a TCM 199 medium, at 37 degrees C, and then insulin binding (37 degrees C, 60 min) and 3-O-methylglucose transport (37 degrees C, 2 s) were determined. Decreased insulin binding was demonstrated in the cells incubated with insulin for 8 h, and Scatchard analysis revealed that receptor number was decreased to 61.7% of that of control cells. Thus, insulin-induced down regulation of receptors was evident after 8 h incubation with insulin. On the other hand, 8 h incubation with insulin resulted in markedly increased basal (i.e., in the absence of insulin) glucose transport up to 246% of control values. In the cells incubated with insulin for 24 h, maximally insulin-stimulated glucose transport was significantly increased up to 248% of control value. Thus, these results suggested that insulin-induced down regulation of receptors appeared to be coupled with increased cell-surface glucose transporters, and that there was a time-lag between down regulation of insulin receptors and increase of available glucose transporters in the plasma membrane.
采用大鼠脂肪细胞，以时间依赖性方式研究了胰岛素对胰岛素结合及葡萄糖转运的长期体外效应。将分离的脂肪细胞在37℃下于TCM 199培养基中与胰岛素（100 ng/ml）孵育4、8和24小时，然后测定胰岛素结合（37℃，60分钟）和3 - O - 甲基葡萄糖转运（37℃，2秒）。在与胰岛素孵育8小时的细胞中，胰岛素结合减少，Scatchard分析显示受体数量降至对照细胞的61.7%。因此，与胰岛素孵育8小时后，胰岛素诱导的受体下调明显。另一方面，与胰岛素孵育8小时导致基础（即无胰岛素时）葡萄糖转运显著增加，高达对照值的246%。在与胰岛素孵育24小时的细胞中，最大胰岛素刺激的葡萄糖转运显著增加，高达对照值的248%。因此，这些结果表明，胰岛素诱导的受体下调似乎与细胞表面葡萄糖转运体增加相关，并且胰岛素受体下调与质膜中可用葡萄糖转运体增加之间存在时间滞后。
