Effects of simulated hyperglycemia, insulin, and glucagon on endothelial nitric oxide synthase expression
Effects of simulated hyperglycemia, insulin, and glucagon on endothelial nitric oxide synthase expression
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DOI：
10.1152/ajpendo.2000.279.1.e11
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发表时间：
2000-07-01
影响因子：
5.1
通讯作者：
Roh, DD
中科院分区：
文献类型：
--
作者：
Ding, YX;Vaziri, ND;Roh, DD
糖尿病与内皮功能障碍和高血压、心血管疾病和肾脏并发症的风险增加有关。早期的研究表明，高血糖症损害一氧化氮（NO）的产生，糖尿病导致人类和实验动物的内皮功能障碍。本研究旨在测试葡萄糖、胰岛素和胰高血糖素浓度的改变对培养的人冠状动脉内皮细胞中NO产生和内皮NO合酶（eNOS）表达的影响，这些是I型和II型糖尿病的主要变量。培养的内皮细胞在正常（5.6 mM）或高（25 mM）浓度的葡萄糖存在下孵育7天。然后在基础条件下以及在胰岛素（10（-8）和10（-7）M）、胰高血糖素（10（-8）和10（-7）M）或两者同时存在的情况下，测定基础和缓激肽刺激的NO产生（硝酸盐+亚硝酸盐）和eNOS蛋白表达（Western印迹法）的速率。孵育7天的高糖浓度显着下调，而胰岛素显着上调，基础和缓激肽刺激的NO生产和eNOS表达在培养的内皮细胞。胰岛素的刺激作用被高葡萄糖浓度所减轻，并被胰高血糖素与细胞共处理所消除。因此，高血糖症，胰岛素减少症，高胰高血糖素血症，这往往并存于糖尿病，可以协同工作，以抑制NO生产的人冠状动脉内皮细胞。
Diabetes is associated with endothelial dysfunction and increased risk of hypertension, cardiovascular disease, and renal complications. Earlier studies have revealed that hyperglycemia impairs nitric oxide (NO) production and diabetes causes endothelial dysfunction in humans and experimental animals. This study was designed to test the effects of altered concentrations of glucose, insulin, and glucagon, the principal variables in types I and II diabetes, on NO production and endothelial NO synthase (eNOS) expression in cultured human coronary endothelial cells. Cultured endothelial cells were incubated in the presence of glucose at either normal (5.6 mM) or high (25 mM) concentrations for 7 days. The rates of basal and bradykinin-stimulated NO production (nitrate + nitrite) and eNOS protein expression (Western blot) were then determined at the basal condition and in the presence of insulin (10(-8) and 10(-7) M), glucagon (10(-8) and 10(-7) M), or both. Incubation with a high-glucose concentration for 7 days significantly downregulated, whereas insulin significantly upregulated, basal and bradykinin-stimulated NO production and eNOS expression in cultured endothelial cells. The stimulatory action of insulin was mitigated by high-glucose concentration and abolished by cotreatment of cells with glucagon. Thus hyperglycemia, insulinopenia, and hyperglucagonemia, which frequently coexist in diabetes, can work in concert to suppress NO production by human coronary artery endothelial cells.