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Neural Regulation of Glucose Transport System in Peripheral Tissues.

周围组织中葡萄糖转运系统的神经调节。

基本信息

批准号：
01570161
负责人：
SHIMAZU Takashi
金额：
$ 1.28万
依托单位：
Ehime University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

项目摘要

To clarify the role of the ventromedial hypothalamus (VMH) -sympathetic nervous system in insulin-independent glucose transport in peripheral tissues, tissue glucose uptake was assessed in vivo by the 2-[^3H]deoxyglucose method during electrical and chemical stimulation of the VMH in anesthetized rats. VMH stimulation increased the rate constant of glucose uptake in brown adipose tissue (BAT) (about 10-fold), heart (3-fold) and skeletal muscles (1.5-fold), but not in white adipose tissue, diaphragm and brain. The effect of VMH stimulation on glucose uptake in BAT was abolished by local sympathetic denervation, indicating that the increase in glucose uptake is mediated by the sympathetic nerves. Electrical stimulation of the lateral hypothalamus, on the other hand, had no appreciable effects on 2-[^3H] deoxyglucose uptake in any tissues.The mechanism of hypothalamic effect on glucose uptake was analyzed by measuring D-glucose transport in vitro, using sarcolemmal membrane vesicles isolated from heart muscle. Non-specific L-glucose transport was subtracted from D-glucose value to obtain specific D-glucose transport. It was found that VMH stimulation caused significant increase in D-glucose transport in heart plasma membrane, as observed after insulin treatment.Changes in glucose transporters after VMH stimulation were also examined by the [^3H] cytochalasin B binding method using heart sarcolemmal membrane. Scatchard analysis of cytochalasin B binding indicated that VMH stimulation did not alter both the number and affinity (dissociation constant) of glucose transporters in the heart sarcolemmal membrane, whereas insulin administration increased the number of transporters in the membrane. These results suggest that the mechanism by which VMH-sympathetic nervous system enhances glucose uptake in certain tissues is different from that of insulin, probably deriving from an activation of glucose transporter molecule in the plasma membrane.

为了阐明腹内侧下丘脑（VMH）-交感神经系统在外周组织胰岛素非依赖性葡萄糖转运中的作用，在电刺激和化学刺激麻醉大鼠VMH期间，采用2-[^3H]脱氧葡萄糖法在体内评估组织葡萄糖摄取。VMH刺激使棕色脂肪组织（BAT）（约10倍）、心脏（3倍）和骨骼肌（1.5倍）的葡萄糖摄取速率常数增加，但在白色脂肪组织、膈肌和脑中没有增加。VMH刺激对BAT葡萄糖摄取的影响被局部交感神经切断所消除，表明葡萄糖摄取的增加是由交感神经介导的。另一方面，电刺激外侧下丘脑对任何组织的2-[^3H]脱氧葡萄糖摄取都没有明显的影响，通过测量离体D-葡萄糖转运，使用从心肌分离的肌膜囊泡，分析了下丘脑对葡萄糖摄取的作用机制。从D-葡萄糖值中减去非特异性L-葡萄糖转运以获得特异性D-葡萄糖转运。用心肌细胞膜[^3 H]细胞松弛素B结合法检测了VMH刺激后心肌细胞膜葡萄糖转运蛋白的变化。细胞松弛素B结合的Scatchard分析表明，VMH刺激没有改变心脏肌膜中葡萄糖转运蛋白的数量和亲和力（解离常数），而胰岛素给药增加了膜中转运蛋白的数量。这些结果表明，VMH-交感神经系统在某些组织中增强葡萄糖摄取的机制与胰岛素不同，可能来自质膜中葡萄糖转运蛋白分子的激活。