Draznin B, Sussman K E, Eckel R H, Kao M, Yost T, Sherman N A
Research Service, Veterans Administration Medical Center, Denver, Colorado 80220.
J Clin Invest. 1988 Dec;82(6):1848-52. doi: 10.1172/JCI113801.
Insulin- and glyburide-stimulated changes in cytosolic free calcium concentrations [( Ca2+]i) were studied in gluteal adipocytes obtained from six obese women (139 +/- 3% ideal body wt) and six healthy, normal weight age- and sex-matched controls. Biopsies were performed after an overnight fast and twice (at 3 and 6 h) during an insulin infusion (40 mU/m2 per min) (euglycemic clamp). In adipocytes obtained from normal subjects before insulin infusion, insulin (10 ng/ml) increased [Ca2+]i from 146 +/- 26 nM to 391 +/- 66 nM. Similar increases were evoked by 2 microM glyburide (329 +/- 41 nM). After 3 h of insulin infusion, basal [Ca2+]i rose to 234 +/- 21 nM, but the responses to insulin and glyburide were completely abolished. In vitro insulin-stimulated 2-deoxyglucose uptake was reduced by insulin and glucose infusion (25% stimulation before infusion, 5.4% at 3 h, and 0.85% at 6 h of infusion). In obese patients, basal adipocyte [Ca2+]i was increased (203 +/- 14 nM, P less than 0.05 vs. normals). The [Ca2+]i response demonstrated resistance to insulin (230 +/- 23 nM) and glyburide (249 +/- 19 nM) stimulation. Continuous insulin infusion increased basal [Ca2+]i (244 +/- 24 nM) and there was no response to either insulin or glyburide at 3 and 6 h of study. Rat adipocytes were preincubated with 1-10 mM glucose and 10 ng/ml insulin for 24 h. Measurements of 2-deoxyglucose uptake demonstrated insulin resistance in these cells. Under these experimental conditions, increased levels of [Ca2+]i that were no longer responsive to insulin were demonstrated. Verapamil in the preincubation medium prevented the development of insulin resistance.
在取自6名肥胖女性（体重为理想体重的139±3%）和6名年龄、性别相匹配的健康正常体重对照者的臀肌脂肪细胞中，研究了胰岛素和格列本脲刺激引起的胞浆游离钙浓度（[Ca2+]i）变化。在过夜禁食后以及在胰岛素输注（40 mU/m2每分钟）（正常血糖钳夹）期间（3小时和6小时时）进行活检。在正常受试者胰岛素输注前获取的脂肪细胞中，胰岛素（10 ng/ml）使[Ca2+]i从146±26 nM增加至391±66 nM。2 microM格列本脲（329±41 nM）也引起类似增加。胰岛素输注3小时后，基础[Ca2+]i升至234±21 nM，但对胰岛素和格列本脲的反应完全消失。体外胰岛素刺激的2-脱氧葡萄糖摄取在胰岛素和葡萄糖输注后降低（输注前刺激25%，输注3小时时为5.4%，输注6小时时为0.85%）。在肥胖患者中，基础脂肪细胞[Ca2+]i升高（203±14 nM，与正常对照相比P<0.05）。[Ca2+]i反应显示对胰岛素（230±23 nM）和格列本脲（249±19 nM）刺激存在抵抗。持续胰岛素输注使基础[Ca2+]i升高（244±24 nM），并且在研究的3小时和6小时时对胰岛素或格列本脲均无反应。大鼠脂肪细胞在1 - 10 mM葡萄糖和10 ng/ml胰岛素中预孵育24小时。2-脱氧葡萄糖摄取测量显示这些细胞存在胰岛素抵抗。在这些实验条件下，证明[Ca2+]i水平升高且不再对胰岛素有反应。预孵育培养基中的维拉帕米可防止胰岛素抵抗的发生。
