Identification of persistent defects in insulin receptor structure and function capillary endothelial cells from diabetic rats.
Identification of persistent defects in insulin receptor structure and function capillary endothelial cells from diabetic rats.
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DOI：
10.1172/jci113848
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发表时间：
1989
期刊：
影响因子：
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通讯作者：
C. Kwok;B. Goldstein;D. Muller–Wieland;T. S. Lee;C. Kahn;G. King
中科院分区：
文献类型：
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作者：
C. Kwok;B. Goldstein;D. Muller–Wieland;T. S. Lee;C. Kahn;G. King
研究了糖尿病大鼠及其非糖尿病配偶培养的毛细血管内皮细胞中胰岛素的作用和受体。2月龄糖尿病大鼠内皮细胞在培养过程中存在持续性的生物学和生化缺陷。与正常大鼠相比，糖尿病大鼠内皮细胞的生长速度慢44%。胰岛素与胰岛素样生长因子I （IGF-I）的结合研究表明，糖尿病大鼠细胞的胰岛素受体结合降低了50%（非糖尿病大鼠：4.6 +/- 0.7；糖尿病大鼠：2.6 +/- 0.4%,P < 0.01），这是由于每毫克蛋白质的结合位点数量减少了50%引起的，而IGF-I的结合没有改变。胰岛素刺激的2-脱氧葡萄糖摄取和α -氨基异丁酸摄取也严重受损，最大刺激减少80-90%，同时胰岛素刺激的自磷酸化减少62% （P < 0.05）。125i -胰岛素交联显示胰岛素受体的140-kD α亚基与非糖尿病大鼠细胞相似，尽管也检测到大于200 kD的条带。胰岛素受体β亚基的分子量（SDS-PAGE）在糖尿病大鼠细胞中小于正常大鼠（88-90 vs. 95 kD）。神经氨酸酶处理部分纯化的胰岛素受体，使非糖尿病大鼠胰岛素受体的分子量比糖尿病大鼠更大程度地降低。相比之下，使用人cDNA探针对胰岛素受体mRNA进行Northern blot分析发现，糖尿病大鼠和非糖尿病大鼠细胞的mRNA丰度分别为9.4和7.2 kb，没有差异。我们得出结论，毛细血管内皮细胞暴露于体内糖尿病环境可引起胰岛素受体和胰岛素作用的特异性和持续性变化。
Insulin actions and receptors were studied in capillary endothelial cells cultured from diabetic BB rats and their nondiabetic colony mates. The endothelial cells from diabetic rats of 2 mo duration had persistent biological and biochemical defects in culture. Compared with normal rats, endothelial cells from diabetic rats grew 44% more slowly. Binding studies of insulin and insulin-like growth factor I (IGF-I) showed that cells from diabetic rats had 50% decrease of insulin receptor binding (nondiabetic: 4.6 +/- 0.7; diabetic: 2.6 +/- 0.4% per milligram protein, P less than 0.01), which was caused by a 50% decrease in the number of binding sites per milligram protein, whereas IGF-I binding was not changed. Insulin stimulation of 2-deoxy-glucose uptake and alpha-aminoisobutyric acid uptake were also severely impaired with a 80-90% decrease in maximal stimulation, in parallel with a 62% decrease in insulin-stimulated autophosphorylation (P less than 0.05). 125I-insulin cross-linking revealed an 140-kD alpha subunit of the insulin receptor similar to that in cells from nondiabetic rats, although bands at greater than 200 kD were also detected. The molecular weight of the insulin receptor beta subunit (by SDS-PAGE) was smaller in cells from diabetic than from normal rats (88-90 vs. 95 kD). Neuraminadase treatment of the partially purified insulin receptors decreased the molecular weight of the insulin receptors from nondiabetic rats to a greater degree than its diabetic counterpart. In contrast, Northern blot analysis of insulin receptor mRNAs using human cDNA probes revealed two species of 9.4 and 7.2 kb with no difference in mRNA abundance between cells from diabetic and nondiabetic rats. We conclude that the exposure of capillary endothelial cells to a diabetic milieu in vivo can cause specific and persistent changes in the insulin receptor and insulin action.