高血糖对大鼠脑出血后血脑屏障葡萄糖转运蛋白1表达的影响

[目的]观察高血糖对大鼠脑出血血肿周围血脑屏障葡萄糖转运蛋白1(GLUT1)表达的影响.[方法]32只雄性SD大鼠随机分为4组:正常血糖组,高血糖组,正常血糖脑出血组,高血糖脑出血组,自体血注入法建立脑出血大鼠模型,免疫组化检测GLUT1的表达.[结果]脑出血早期,4组大鼠血脑屏障GLUT1均有表达,高血糖组大鼠GLUT1表达低于正常血糖组;高血糖脑出血组GLUT1的表达低于正常血糖脑出血组.[结论]高血糖可降低脑出血后大鼠血脑屏障GLUT1的表达.     

耐力运动对大鼠葡萄糖运载体基因表达及转位的影响

目的　研究耐力运动对大鼠骨骼肌细胞葡萄糖运载体 4(glucosetransporter 4,GLUT4)基因表达及转位机制的影响。方法　将SD大鼠随机分为两组 :对照组和耐力运动组。耐力运动组大鼠进行 6周游泳训练。用Western印迹法检测大鼠骨骼肌细胞内膜和外膜的GLUT4蛋白含量 ,用Northern杂交法和斑点印迹法检测大鼠骨骼肌细胞内GLUT4mRNA含量。实验前后检测大鼠血清胰岛素和血糖浓度。结果　运动组大鼠经过 6周游泳训练后 ,与对照组大鼠相比 ,骨骼肌细胞内膜GLUT4含量增加 16.0 %(P <0 .0 1) ,细胞外膜GLUT4含量增加 71.9% (P <0 .0 1) ,骨骼肌细胞内GLUT4mRNA含量增加2 5 .6% (P <0 .0 1)。结论　耐力运动可增加骨骼肌细胞内GLUT4基因表达水平 ,促进骨骼肌细胞内的GLUT4从内膜向细胞外膜转位 ,从而提高骨骼肌细胞对葡萄糖的摄取和利用。     

脂肪干细胞对大鼠胰岛细胞脂性凋亡的保护作用

[目的]探讨脂肪干细胞(ADSCs)对棕榈酸(PA)诱导大鼠胰岛瘤细胞(INS-1)凋亡的保护作用.[方法]本实验分为三组.空白对照组:正常培养液+INS-1单独培养(其上层只含培养基);PA组:含0.5 mmol/L PA的高脂培养液+INS-1单独培养;INS-1+ ADSCs组:高脂培养液+INS-1+ ADSCs共培养.各组在处理24 h后检测各组细胞的存活率、胰岛细胞基础胰岛素分泌量(BIS)和葡萄糖刺激的胰岛素分泌量(GSIS);采用RT-PCR检测胰岛细胞中Ins-1、Glut-2、Pdx-1表达量;采用Elisa检测各组IL-6、TNF-α、HGF、TIMP-1和TGF-β水平.[结果]PA组和PA+ ADSCs组细胞存活率均较对照组下降(P＜0.01),但PA+ ADSCs组细胞存活率明显大于PA组(P＜0.01).与对照组相比,PA组和PA+ ADSCs组BIS增加(P＜0.01),而GSIS均减少(P＜0.01);与PA组比较,PA+ ADSCs组细胞BIS差异无统计学意义(P＞0.05),而GSIS显著增加(P＜0.01).和对照组相比,PA组和PA+ ADSCs组的Pdx-1、Ins-1、Glut-2 mRNA水平均明显下降(P＜0.01);和PA相比,PA+ ADSCs组细胞的Pdx-1和Glut-2 mRNA水平明显上升(P＜0.01),而Ins-1 mRNA水平比较差异无统计学意义(P＞0.05).PA+ ADSCs组中IL-6、TNF-α、HGH、TIMP-1、TGF-β的含量均较其他两组明显升高.[结论]PA能诱导INS-1细胞凋亡并抑制Ins-1、Glut-2、Pdx-1的表达,而ADSCs可以通过旁分泌机制并上调Glut-2和Pdx-1的表达对胰岛细胞起到保护作用.     

小牛血清去蛋白注射液对2型糖尿病大鼠糖耐量及骨骼肌GLUT4mRNA表达的影响——附90例报告

目的：探讨小牛血清去蛋白注射液（deproteinized calf serum injection,DCSI）对2型糖尿病模型大鼠的糖耐量及骨骼肌的葡萄糖转运子4（glucose transporter4,GLUT4）mRNA表达的影响。方法：将90只3月龄健康远交系大鼠随机分为6组,每组15只。分别制作正常对照组（正常组）、糖尿病对照组（糖尿病组）、罗格列酮对照组（罗格列酮组）、DCSI高剂量组（高剂量组）、DCSI中等剂量组（中等剂量组）、DCSI低剂量组（低剂量组）等6组模型。在给药4周后行葡萄糖耐量试验,分别测定6组餐后0min、30min、1h、2h的血糖水平;次日处死小鼠,采用逆转录PCR法检测6组大鼠模型骨骼肌中GLUT4mRNA的相对表达量。结果：糖尿病组、低剂量组、中等剂量组、高剂量组、罗格列酮各时间段的血糖水平均高于正常组（均为P〈0．01）。低剂量组、中等剂量组、高剂量组和罗格列酮组的各时间段的血糖水平均明显低于糖尿病组（均为P〈0．01）。上述4组治疗组中,低剂量组、高剂量组餐后1h、餐后2h的血糖水平均高于罗格列酮组（均为P〈0．05）,中等剂量组餐后1h、餐后2h的血糖水平与罗格列酮组比较差异则无统计学意义（均为P〉0．05）。另外,糖尿病组的骨骼肌GLUT4mRNA的相对表达量明显低于正常组。罗格列酮组、低剂量组、中等剂量组及高剂量组GLUT4mRNA的相对表达量明显高于糖尿病组。上述4组治疗组中,中等剂量组GLUT4mRNA的相对表达量最高,接近于正常组。结论：DCSI尤其是中等剂量的DCSI可改善2型糖尿病模型大鼠的糖耐量,使其骨骼肌的GLUT4mRNA表达量增加。     

运动对胰岛素抵抗大鼠脂肪细胞葡萄糖转运蛋白-4的影响

目的研究运动对高糖高脂饮食诱导的胰岛素抵抗大鼠脂肪细胞葡萄糖转运蛋白4(GLUT4)的影响。方法将实验大鼠随机分为正常组、模型组和运动组,每组各10只。各组以基础饲料适应性喂养1周后,模型组和运动组改用高糖、高脂饲料喂养,第5周时运动组进行为期6周的游泳训练。各组于实验第1,5和11周检测大鼠的体重、血甘油三酯、血胆固醇、空腹血糖和血浆胰岛素水平,计算胰岛素敏感指数。采用Westernblot法检测大鼠脂肪细胞内、外膜GLUT4含量。结果模型组大鼠与正常组相比,脂肪细胞内、外膜GLUT4含量均显著降低,差异均有统计学意义(P<0.05)。与模型组相比,经过6周游泳训练的运动组大鼠脂肪细胞内膜GLUT4含量无明显变化,而细胞外膜GLUT4含量显著增加,差异有统计学意义(P<0.05)。结论运动可提高胰岛素抵抗大鼠脂肪细胞外膜GLUT4含量,促进葡萄糖的摄取和利用。     

3-硝基丙酸对大鼠缺血再灌注损伤葡萄糖转运蛋白3表达的影响

目的:探讨3-硝基丙酸(3-NPA)对大鼠缺血再灌注损伤葡萄糖转运蛋白3(GLUT3)表达的影响.方法:雄性SD大鼠50只,随机分为假手术组(sham组,n=4)、预处理对照组(3-NPA组,n=4)、大脑中动脉缺血组(M组,n=21)、3-NPA预处理组(IPC组,n=21).其中M组和IPC组各5只,用于神经缺损体征评分和大鼠脑梗死体积的测定;余按再灌注时间(4、12、24及48 h)不同又分为4个亚组(n=4),分别采用Western Blot和RT-PCR,检测GLUT3蛋白和GLUT3 mRNA基因水平表达情况.结果:IPC组比M组的GLUT3蛋白表达增高,差异有显著性(P<0.05),IPC组GLUT3 mRNA表达在24 h增高,48 h最高,与M组相应时间点24、48 h及Sham组比较显著增高.结论:3-NPA预处理诱导脑缺血耐受,GLUT3蛋白和GLUT3mRNA基因水平表达上调,维持脑组织的能量供给是其可能机制之一.     

金双歧联合葡萄糖酸锌治疗小儿厌食症疗效观察

[目的]评价金双歧加葡萄糖酸锌治疗小儿厌食症的临床效果.[方法]将73例厌食症患儿随机分为观察组37例和对照组36例;对照组给予金双歧片口服治疗,观察组在对照组的基础上加服葡萄糖酸锌片;用药4周后观察两组患儿的临床疗效和用药安全性,ELISA法检测治疗前后两组患儿血清中瘦素（Leptin）、胃促生长素（Ghrelin）的水平变化.[结果]观察组的临床总有效率为91.89％,与对照组的69.44％比较差异有统计学意义（P＜0.05）;两组患儿治疗后血清中Leptin水平增加、Ghrelin水平降低,与治疗前比较差异均有统计学意义（P＜0.05）,且观察组优于对照组（P＜0.05）;两组不良反应比较差异无显著性（P＞0.05）.[结论]金双歧加葡萄糖酸锌治疗小儿厌食症安全有效,其促食欲的作用可能与Leptin和Ghrelin的分泌调节有关.     

运动对糖尿病大鼠骨骼肌细胞葡萄糖运载体4转位机制的影响

目的　研究运动对链脲佐菌素 (STZ)引起的糖尿病大鼠骨骼肌细胞葡萄糖运载体 4(Glucosetransporter 4,GLUT4)转位机制的影响。 方法　将实验大鼠分为 3组 :正常对照组、糖尿病组和糖尿病运动组。糖尿病运动组大鼠进行 6周游泳训练。实验到期分离各组大鼠大腿股四头肌 ,制备细胞内、外膜 ,以Western印迹法检测GLUT4蛋白含量 ,同时检测大鼠血清胰岛素和血糖浓度。结果　糖尿病大鼠骨骼肌细胞GLUT4蛋白含量明显减少 ,与正常对照组相比 ,细胞内膜GLUT4蛋白含量减少 2 4.1% (P <0 .0 1) ,细胞外膜减少 48.1% ,(P <0 .0 1)。糖尿病大鼠经过 6周运动训练 ,与糖尿病组大鼠相比 ,骨骼肌细胞内膜GLUT4蛋白含量无明显变化 ,而细胞外膜GLUT4蛋白含量增加 10 8.7% (P <0 .0 1) ,血糖由18.5± 1.9mmol/L降至 14 .0± 3 .3mmol/L(P <0 .0 1)。结论　糖尿病状态下骨骼肌细胞GLUT4蛋白含量明显减少 ,其中以细胞外膜GLUT4蛋白含量的减少更为显著 ,即在糖尿病状态下骨骼肌细胞GLUT4蛋白转位机制出现障碍 ,使肌细胞对葡萄糖的转运发生障碍 ,血糖升高。糖尿病大鼠经过运动训练可增加骨骼肌细胞GLUT4蛋白含量 ,并改善GLUT4蛋白转位机制 ,从而增加肌细胞对葡萄糖的转运和利用 ,降低血糖 ,改善糖尿病大鼠糖代谢紊乱的状况。     

高糖、胰岛素影响肾小球系膜细胞葡萄糖转运蛋白4 mRNA表达的研究

目的:探讨高糖、胰岛素对肾小球系膜细胞葡萄糖转运蛋白4 mRNA表达的影响,进一步研究GluT4在糖尿病肾病发病中的作用。方法:将培养的鼠1097系膜细胞分为8组:正常对照组,生理浓度胰岛素组(10-9M),低浓度胰岛素组(10-8M),高浓度胰岛素组(10-6M),高糖组(30mM),甘露醇组,高糖加高浓度胰岛素组,高糖加生理浓度胰岛素组。采用RT-PCR法检测GluT4 mRNA含量。结果:①正常系膜细胞可检测到GluT4mRNA。②高糖组GluT4 mRNA表达为对照组的58.7%(p<0.05);10-8M胰岛素组、10-6M胰岛素组分别为对照组的230.2%和297.2%(P<0.01);高糖加10-6M胰岛素组,高糖加10-9M胰岛素组分别为高糖组的170.6%和140.3%(p<0.05)。结论:①正常系膜细胞有GluT4 mRNA表达。②高糖可抑制GluT4 mRNA表达,胰岛素有一定拮抗作用,且呈剂量依赖性。③GluT4是糖尿病肾病发生发展中的重要因子。     

小鼠骨骼肌细胞蛋白激酶B底物160在有氧运动促进葡萄糖转运体4转运中的作用

目的:通过研究有氧运动对C57BL/6小鼠骨骼肌细胞蛋白激酶B(PKB/Akt)底物蛋白160(AS160)和葡萄糖转运体4(GLUT4)表达的影响,探讨AS160在调节细胞葡萄糖转运过程中的作用及有氧运动影响骨骼肌细胞葡萄糖代谢的生物学机制。方法:20只16周龄、雄性C57BL/6小鼠,随机分为安静组(NC,n=10)和运动组(NE,n=10);运动组进行为期6周、75%VO2max强度的有氧跑台训练。6周训练结束后24h,动物麻醉后取材。采用逆转录聚合酶链反应(RT-PCR)检测骨骼肌组织AS160、GLUT4基因表达;免疫印迹杂交(Western blot)和免疫荧光染色(IF)分别检测骨骼肌细胞AS160、pAS160-Thr642和GLUT4蛋白表达及定位。结果:与NC组相比,NE组小鼠骨骼肌细胞AS160 mRNA和蛋白表达差异无显著性,但pAS160-Thr642表达显著增加;NE组小鼠骨骼肌细胞GLUT4 mRNA和蛋白表达较NC组显著增加,GLUT4向细胞膜迁移明显增加。结论:有氧运动显著增强骨骼肌细胞pAS160-Thr642的活性,增强GLUT4表达及促进GLUT4向细胞膜转移,促进骨骼肌细胞对葡萄糖的摄取和利用。     

2型糖尿病大鼠GLUT4mRNA表达与胰岛素分泌关系的探讨

[目的]探讨2型糖尿病大鼠GLUT4mRNA表达与胰岛素分泌的关系，进一步阐明胰岛素抵抗发病机制。[方法]采用逆转录聚合酶链反应（RT—PCR），分析大鼠骨骼肌、心肌和脂肪组织中GLUT4mRNA表达，放射免疫方法测定血清胰岛素含量。[结果]2型糖尿病大鼠骨骼肌、心肌和脂肪组织中GLUT4mRNA表达比正常对照组相对应组织中的表达低，其基础胰岛素、口服葡萄糖后胰岛素水平比正常对照组显著降低。[结论]2型糖尿病大鼠胰岛素分泌量与组织中GLUT4mRNA表达具有一致性表型。     

高血糖对大鼠肾皮质葡萄糖转运蛋白1 mRNA表达的影响

【摘要】目的探讨葡萄糖转运蛋白1（glucosetransporter1,GLUT1）在糖尿病。肾病（diabeticnephropathy,DN）发病机制中的作用。方法将36只Wistar大鼠随机分为对照组10只、高血糖组及2型糖尿病组各13只,分别采用腹腔内注射链脲佐菌素及高脂饮食加腹腔内注射链脲佐菌素方法制备高血糖及2型糖尿病模型。10W末实验结束后,取大鼠肾皮质,同时检测大鼠体重、肾重、肾重百分比,血清BUN;采用逆转录聚合酶链反应半定量分析肾皮质GLUT1 mRNA的表达。结果高血糖组大鼠的体重显著降低,肾重、肾重百分比、BUN、FPG和ISI水平均高于2型糖尿病组及对照组．差异均有统计学意义（P〈0．05）。而FINS的水平低于2型糖尿病组及对照组,差异亦均有统计学意义（P均〈0．05）。高血糖组和2型糖尿病组GLUTlmRNA在‘肾皮质中的表达均显著高于对照组．且高血糖组GLUT1mR．NA在肾皮质的表达显著高于2型糖尿病组（P均〈0．05）。结论GLUT1在肾皮质中有表达．高血糖可以上调肾皮质GLUT1表达,GLUT1可能与DN的发病相关。     

Differential regulation of adipose tissue glucose transporters in genetic obesity (fatty rat). Selective increase in the adipose cell/muscle glucose transporter (GLUT 4) expression.

Adipocytes from young obese Zucker rats exhibit a hyperresponsive insulin-mediated glucose transport, together with a marked increase in cytochalasin B binding as compared with lean rat adipocytes. Here, we examined in these cells the expression of two isoforms of glucose transporter, the erythroid (GLUT 1) and the adipose cell/muscle (GLUT 4) types, in rats aged 16 or 30 d, i.e., before and after the emergence of hyperinsulinemia. GLUT 1 protein and mRNA levels were identical in the two genotypes at both ages. In contrast, the levels of GLUT 4 protein in obese rat adipocytes were 2.4- and 4.5-fold those of lean littermates at 16 and 30 d of age, respectively, in perfect agreement with the genotype effect on insulin-stimulated glucose transport activity. The levels of GLUT 4 mRNA per fat pad were increased 2.3- and 6.2-fold in obese vs. lean rats 16- and 30-d-old, indicating a pretranslational level of regulation. The obese phenotype was not associated with overexpression of GLUT 4 mRNA in gastrocnemius muscle. This work indicates that the fa gene exerts a differential control on the expression of GLUT 1 and GLUT 4 in adipose tissue and provides evidence that independent of hyperinsulinemia, genotype is a major regulatory factor of GLUT 4 expression in this tissue.     

Evidence from oocyte expression that the erythrocyte water channel is distinct from band 3 and the glucose transporter.

It has been proposed that the mercurial-sensitive water transporter in mammalian erythrocytes is the anion exchanger band 3 (AE1) and/or the glucose transporter, band 4.5 (GLUT1). Using a functional assay for water channel expression in Xenopus oocytes (Zhang, R., K. A. Logee, and A. S. Verkman. 1990. J. Biol. Chem. 265:15375-15378), we compared osmotic water permeability (Pf) of oocytes injected with water, reticulocyte mRNA, AE1 mRNA, and GLUT1 mRNA. Injection of oocytes with 5-50 ng of in vitro-transcribed AE1 mRNA had no effect on Pf, but increased trans-stimulated 36Cl uptake greater than fourfold in a dinitro-disulfonic stilbene (DNDS)-inhibitable manner. Injection with 1-50 ng of in vitro-transcribed GLUT1 mRNA increased 3H-methylglucose uptake greater than 15-fold in a cytochalasin B-sensitive manner and increased Pf from (3.7 +/- 0.4) x 10(-4) cm/s (SE, n = 16, 10 degrees C) in water-injected oocytes up to (13 +/- 1) x 10(-4) cm/s (n = 18). Both the increments in sugar and water transport were inhibited by cytochalasin B (25 microM) and phloretin (0.2 mM); neither was inhibited by 0.3 mM HgCl2. In oocytes injected with 50 ng of rabbit reticulocyte mRNA, the Pf of (18 +/- 2) x 10(-4) cm/s (n = 18) was reduced to (4.0 +/- 0.6) x 10(-4) cm/s (n = 10) by HgCl2, but was not inhibited by DNDS (0.4 mM), cytochalasin B or phloretin. Coinjection of reticulocyte mRNA with antisense oligodeoxyribonucleotides against AE1 or GLUT1 did not affect Pf, but inhibited completely the incremental uptake of 36Cl or 3H-methylglucose, respectively. Expression of size-fractionated mRNA from reticulocyte gave a 2-2.5-kb size for water channel mRNA, less than the 4-4.5-kb size for the Cl transporter. These results provide evidence that facilitated water transport in erythrocytes is mediated not by bands 3 or 4.5, but by distinct water transport protein(s).     

Concentration of Myo-inositol in Skeletal Muscle of the Rat Occurs without Active Transport

The cellular uptake of nonphosphorylated myo-inositol (MI) and its incorporation into phosphoinositide in the rat epitrochlearis muscle was measured. Cellular uptake of [2-³H]MI was determined by the difference between total uptake and [2-³H]MI present in the extracellular fluid determined with [1-¹⁴C]mannitol. Cellular uptake was parabolic and directly proportional to medium MI concentrations between 25 and 3,200 μM. Saturation of a MI carrier was not evident. Moreover, uptake was not inhibited by 2 mM ouabain, 0.3 mM 2,4-dinitrophenol, or 22 mM glucose. Insulin, 100 mU/ml, was without effect on either cellular uptake of [2-³H]MI or its incorporation into phosphoinositides. In muscles that were preloaded with [2-³H]MI and then incubated in media that contained a constant amount of MI but no [2-³H]MI, 44.3% of the [2-³H]MI was released after 10 min increasing to 62.5% by 120 min. Cellular MI concentrations were 0.18 μmol/g wet tissue (four times plasma levels) in rapidly isolated and frozen epitrochlearis muscle. When muscle was incubated without MI, 48% of endogenous MI was lost rapidly. Restoration of cellular MI in 50 μM MI media occurred in two phases, a rapid uptake phase lasting 10 min and a subsequent slow phase of MI uptake.     

Pretranslational suppression of a glucose transporter protein causes insulin resistance in adipocytes from patients with non-insulin-dependent diabetes mellitus and obesity

A major portion of insulin-mediated glucose uptake occurs via the translocation of GLUT 4 glucose transporter proteins from an intracellular depot to the plasma membrane. We have examined gene expression for the GLUT 4 transporter isoform in subcutaneous adipocytes, a classic insulin target cell, to better understand molecular mechanisms causing insulin resistance in non-insulin-dependent diabetes mellitus (NIDDM) and obesity. In subgroups of lean (body mass index [BMI] = 24 +/- 1) and obese (BMI = 32 +/- 2) controls and in obese NIDDM (BMI = 35 +/- 2) patients, the number of GLUT 4 glucose transporters was measured in total postnuclear and subcellular membrane fractions using specific antibodies on Western blots. Relative to lean controls, the cellular content of GLUT 4 was decreased 40% in obesity and 85% in NIDDM in total cellular membranes. In obesity, cellular depletion of GLUT 4 primarily involved low density microsomes (LDM), leaving fewer transporters available for insulin-mediated recruitment to the plasma membrane (PM). In NIDDM, loss of GLUT 4 was profound in all membrane subfractions, PM, LDM, as well as high density microsomes. These observations corresponded with decrements in maximally stimulated glucose transport rates in intact cells. To assess mechanisms responsible for depletion of GLUT 4, we quantitated levels of mRNA specifically hybridizing with human GLUT 4 cDNA on Northern blots. In obesity, GLUT 4 mRNA was decreased 36% compared with lean controls, and the level was well correlated (r = + 0.77) with the cellular content of GLUT 4 protein over a wide spectrum of body weight. GLUT 4 mRNA in adipocytes from NIDDM patients was profoundly reduced by 86% compared with lean controls and by 78% relative to their weight-matched nondiabetic counterparts (whether expressed per RNA, per cell, or for the amount of CHO-B mRNA). Interestingly, GLUT 4 mRNA levels in patients with impaired glucose tolerance (BMI = 34 +/- 4) were decreased to the same level as in overt NIDDM. We conclude that, in obesity, insulin resistance in adipocytes is due to depletion of GLUT 4 glucose transporters, and that the cellular content of GLUT 4 is determined by the level of encoding mRNA over a wide range of body weight. In NIDDM, more profound insulin resistance is caused by a further reduction in GLUT 4 mRNA and protein than is attributable to obesity per se. Suppression of GLUT 4 mRNA is observed in patients with impaired glucose tolerance, and therefore, may occur early in the evolution of diabetes. Thus, pretranslational suppression of GLUT 4 transporter gene expression may be an important mechanism that produces and maintains cellular insulin resistance in NIDDM.     

Coordinate regulation of glucose transporter function, number, and gene expression by insulin and sulfonylureas in L6 rat skeletal muscle cells.

The extrapancreatic actions of sulfonylureas on the glucose transport system were studied in the L6 line of cultured rat skeletal muscle cells. Insulin (10(-7) M) increased 2-deoxyglucose uptake in differentiated L6 myotubes by 30-40% after 8 h of incubation. The sulfonylurea tolazamide (0.6 mg/ml, 22 h) had no effect on glucose uptake in the absence of insulin, but increased insulin-stimulated 2-deoxyglucose uptake twofold. The total cellular content of glucose transporters was assessed with a monoclonal anti-transporter antibody by a solid-phase ELISA method. Insulin (8 h) increased the quantity of glucose transporters, with a maximal twofold increase at 10(-7) M and a dose-response curve similar to that for insulin stimulation of glucose uptake. In spite of its lack of effect on glucose uptake, tolazamide alone (0.6 mg/ml) increased the cellular content of transporters by 70%. The effects of insulin and tolazamide on transporter gene expression were studied with probes derived from Hep G2 glucose transporter cDNA. Insulin increased the transporter mRNA level 1.7-fold, tolazamide increased it 1.5-fold, and the combination of insulin and tolazamide increased transporter mRNA 3-fold. It is concluded that sulfonylureas, together with insulin, enhance glucose uptake in L6 skeletal muscle cells by increasing the number of functioning glucose transport molecules. The long-term regulation of the glucose transport system in skeletal muscle by insulin and sulfonylureas in vivo may involve similar changes in transporter function, number, and gene expression.     

Tumor necrosis factor-alpha alters glucose metabolism in suckling rats.

Tumor necrosis factor-alpha (TNF-alpha), an important mediator of endotoxic shock, induces hypoglycemia and shock in adult animals. Indomethacin ameliorates TNF-alpha-induced hypoglycemia in the adult. However, effects of TNF-alpha on glucose metabolism in the newborn have not been well documented. The present study showed that in 10-day-old rats injected with TNF-alpha (4.5 x 10(7) U/kg, intraperitoneally) the plasma glucose concentration increased from 4.1 +/- 0.3 mmol/L to 6.9 +/- 0.5 mmol/L (P < .05) at 2 hours and subsequently decreased to 1.4 +/- 0.5 mmol/L (P < .05) at 6 hours, although plasma lactate concentration increased from 1.1 +/- 0.1 mmol/L to 5.5 +/- 0.3 mmol/L (P < .05) at 6 hours. Plasma insulin concentration remained unchanged throughout the experiment. TNF-alpha increased GLUT 1 messenger RNA (mRNA) abundance in the brain, liver, muscle, and fatty tissue (P < .05). Glucose uptake increased in association with the increase of GLUT1 mRNA abundance. TNF-alpha decreased mRNA abundance of GLUT 2 and phosphoenolpyruvate carboxykinase (PEPCK) in liver, suggesting decreased gluconeogenesis. Indomethacin (1.5 mg/kg 20 minutes before TNF-alpha, intraperitoneally) attenuated the hypoglycemia, the lactacidemia, and the increase of GLUT1 mRNA abundance and glucose uptake. Indomethacin attenuated the decrease of PEPCK mRNA abundance. We concluded that TNF-alpha induced hypoglycemia, increasing GLUT1 mRNA abundance and glucose uptake and decreasing PEPCK mRNA abundance in 10-day-old rats. Indomethacin attenuated the TNF-alpha-induced glucose dyshomeostasis.     

NOD1在肥胖糖尿病患者脂肪细胞中的表达及对胰岛素抵抗的作用

【目的】探讨肥胖糖尿病（DM）患者脂肪细胞免疫受体核苷酸结合寡聚化结构域蛋白1（nucleotide-binding oligomerization domain-containing protein,NOD1）的表达与胰岛素抵抗的关系。【方法】取10例肥胖 DM患者（DM组）及10例非DM肥胖患者（NDM组）腹部皮下脂肪细胞,采用Real-time PCR方法检测两组脂肪细胞受体 NOD1的表达,加入 NOD1受体激动剂 iE-DAP,用酶联免疫吸附法（ELISA）检测两组细胞炎性细胞因子白细胞介素（IL）-6、IL-8及单核细胞趋化因子1（MCP-1）水平,2-脱氧-3 H-D-葡萄糖摄入法观察基础状态和 iE-DAP刺激状态的葡萄糖摄取率。【结果】DM组脂肪细胞 NOD1 mRNA的表达显著高于 NDM组（P＜0．05）;iE-DAP刺激下DM组 IL-6、IL-8及 MCP-1的分泌水平均显著高于 NDM组（P ＜0．05）,DM组胰岛素刺激状态下脂肪细胞葡萄糖摄取率显著低于 NDM组（P＜0．05）。【结论】NOD1介导的炎症反应可能参与肥胖糖尿病胰岛素抵抗的发生。     

Decreased in vivo glucose uptake but normal expression of GLUT1 and GLUT4 in skeletal muscle of diabetic rats.

This study was designed to determine whether altered glucose transporter expression is essential for the in vivo insulin-resistant glucose uptake characteristic of streptozocin-induced diabetes. Immunofluorescence in rat skeletal muscle colocalizes GLUT4 with dystrophin, both intrinsic to muscle fibers. In contrast, GLUT1 is extrinsic to muscle fibers, probably in perineurial sheath. Immunoblotting shows that levels of GLUT1 and GLUT4 protein per DNA in hindlimb muscle are unaltered from control levels at 7 d of diabetes but decrease to approximately 20% of control at 14 d of diabetes. This decrease is prevented by insulin treatment. In adipose cells of 7 d diabetic rats, GLUT4 levels are depressed. Thus, GLUT4 undergoes tissue-specific regulation in response to diabetes. GLUT4 and GLUT1 mRNA levels in muscle are decreased 62-70% at both 7 and 14 d of diabetes and are restored by insulin treatment. At 7 d of diabetes, when GLUT4 protein levels in muscle are unaltered, in vivo insulin-stimulated glucose uptake measured by euglycemic clamp is 54% of control. This reflects impairment in both glycogen synthesis and glycolysis and the substrate common to these two pathways, glucose-6-phosphate, is decreased approximately 30% in muscle of diabetic rats. These findings suggest a defect early in the pathway of glucose utilization, probably at the step of glucose transport. Because GLUT1 and GLUT4 levels are unaltered at 7 d of diabetes, reduced glucose uptake in muscle probably reflects impaired glucose transporter translocation or intrinsic activity. Later, at 14 d of diabetes, GLUT1 and GLUT4 protein levels are reduced, suggesting that sequential defects may contribute to the insulin-resistant glucose transport characteristic of diabetes.