生物钟与血糖调节密切相关

一项最新研究发现,生物钟与血糖调节密切相关,这一发现将更好地帮助人们调节人体血糖水平。     

细胞骨架对凝血酶诱导人血小板分泌反应的调节

本文利用血小板表面外露的ＧＭＰ－１４０为血小板分泌反应的特异性标志,通过放射免疫分析法定量测定血小板表面ＧＭＰ－１４０分子数,研究了细胞骨架抑制剂对凝血酶导血小板分泌反应的影响。结果表明,凝血酶激活使血小板表面ＧＭＰ－１４０的外露明显增加,反应迅速,并在一定范围内呈剂量和时间依赖性;而ＡＤＰ刺激则几乎不引起ＧＭＰ－１４０外露的增加。凝血酶激活前加入不同的细胞骨架抑制剂处理可产生不同的效应：细胞松驰     

胰岛素和胰高血糖素对血糖的调节及其相互作用

从2013年江苏高考题生物卷第30题出发,深入探讨胰岛素和胰高血糖素对血糖稳态的调节机制,以及血糖调节异常(糖尿病)的发病机理。     

Obestatin、Ghrelin与血糖调节

肥胖抑制素（obestatin）和生长激素释放肽（ghrelin）能互相拮抗,参与血糖的调节.其中obestatin与GPR-39（G-protein-coupled receptor 39）结合抑制摄食和胃肠排空、促进胰岛β细胞功能,影响胰岛素的分泌;而ghrelin与生长激素促分泌受体（GHSR1a）结合,促进食欲和胃肠排空,减少脂肪的利用,抑制胰岛细胞凋亡,调节胰岛素的分泌.但两者参与血糖调节的具体机制尚存在争议.     

人细胞骨架调节蛋白基因NELIN cDNA的克隆及特征分析

为寻找和研究心血管系统有关的重要功能基因及表达模式,构建了正常成人心脏和主动脉cDNA文库,并在大规模表达序列标签（ESTs）测定和筛选新的cDNAs全长的基础上,筛选出一个新的基因（GenBank登记号AF114264）。该基因的cDNA全长为2736bp,含有一个1344bp的开放读码框,由于其推测的氨基酸序列与鼠源微管连接蛋白（nexilin）具有很高同源性,所以暂将其命名为NELIN（nexilin-like protein)。Northern印迹和RT－PCR结果表明,该基因的心脏、骨骼肌、动脉和静脉中表达,且该表达有一定的时空特异性,查询GeneMap‘99,该基因定位在梁色体1p31－1p32。结构域分析表明,NELIN很可能参与调节粘着斑和张力纤维形成,并参与粘着斑的信号转导。     

对血糖激素调节的商榷

在《生物学通报》2006年第2期的目次Ⅱ页刊登了徐国恒老师对“胰岛素有抑制胰高血糖素分泌的作用,为何胰高血糖素的产生却能促进胰岛素的产生呢?”问题的解答,我认为徐老师的解答不够清楚,不便于学生的理解。在此与大家进行探讨。     

细胞骨架对凝血酶诱导人血小板分泌反应的调节(英文)

本文利用血小板表面外露的GMP-140为血小板分泌反应的特异性标志,通过放射免疫分析法定量测定血小板表面GMP-140分子数,研究了细胞骨架抑制剂对凝血酶诱导血小板分泌反应的影响。结果表明,凝血酶激活使血小板表面GMP-140的外露明显增加,反应迅速,并在一定范围内呈剂量和时间依赖性;而ADP刺激则几乎不引起GMP-140外露的增加。凝血酶激活前加入不同的细胞骨架抑制剂处理可产生不同的效应:细胞松驰素B(肌动蛋白微丝抑制剂)可明显上调凝血酶诱导的GMP-140外露;而秋水仙素(微管抑制剂)则下调GMP-140的外露;两者同时处理仍呈现明显的上调作用。提示凝血酶作为一种强激活剂,不仅可通过受体-G蛋白-第二信使的途径启动血小板分泌反应,而且可能经诱导肌动蛋白微丝的形成对分泌反应起反馈性负调节作用。微管的存在则可能对凝血酶诱导的分泌反应起促进作用。虽然两种细胞骨架的作用相反,但以微丝的作用为主,两者间无相互拮抗现象。     

建立血糖调节的模型

1教学建议在高中生物学教材中,血糖平衡的调节一直是重要的教学内容,但是,个体水平的调节与稳态,内容比较抽象。以往的教学在设计思路上主要是凭教师讲     

细胞骨架调节蛋白3促进食管鳞癌细胞的增殖、迁移和侵袭

细胞骨架调节蛋白3(diaphanous related formin3,DIAPH3)参与肌动蛋白重塑和调节细胞的运动和黏附,在多种肿瘤发生发展中发挥重要作用,但其在食管鳞状细胞癌(简称:食管鳞癌)中作用尚未见报道。本研究探究DIAPH3在食管鳞癌中的作用及其分子机制。首先,基因表达谱交互分析(gene expression profiling interactive analysis,GEPIA)数据库和免疫组织化学染色法,用于分析食管鳞癌组织中DIAPH3在转录水平和蛋白质水平的表达。结果显示,食管鳞癌组织中DIAPH3mRNA和蛋白质的表达高于癌旁组织,其与肿瘤分化和淋巴结转移密切相关(P<0.05)。利用Western印迹检测食管鳞癌组织中DIAPH3蛋白的表达量。结果表明:与癌旁组织相比,食管鳞癌组织中蛋白质的表达量升高(P<0.05)。再利用CCK-8、划痕愈合实验和Transwell侵袭实验,分别检测细胞的增殖、迁移和侵袭能力。实验结果显示:与对照组相比,干扰DIAPH3组细胞的增殖、迁移和侵袭能力下降(P<0.05),而过表达DIAPH3组细胞的增殖、迁移和侵袭能力增强(P<0.05)。最后,利用Western 印迹检测过表达/干扰DIAPH3细胞中的细胞周期蛋白D1(cyclin D1)、E-钙黏着蛋白(E-cadherin)和波形蛋白(vimentin)的表达。Western 印迹结果显示:与对照组相比,干扰DIAPH3组细胞中,E-钙黏着蛋白表达增加,且波形蛋白和细胞周期蛋白D1表达减少(P<0.05),而过表达DIAPH3组细胞中,E-钙黏着蛋白表达减少,且波形蛋白和细胞周期蛋白D1表达增加(P<0.05)。这些研究表明,DIAPH3促进食管鳞癌细胞的增殖、迁移和侵袭。其结果为食管鳞癌的诊治提供了新思路。     

血管扩张刺激磷蛋白在细胞骨架调节中的作用

细胞骨架动力学的调节在细胞粘附、细胞变形、细胞移动等生理过程中是必需的。血管扩张刺激磷蛋白（vasodilator-stimulated phosphoprotein,VASP）是一种肌动蛋白结合蛋白。该蛋白包含以下结构域：EVH1（Ena／VASP homolog1）区、EVH2（Ena／VASP homolog2）区及PRR（proline—rich regions）区。近年来,研究发现VASP在与细胞骨架调节有关的各种细胞行为中起着重要作用,如神经细胞轴索的延伸、T细胞的移动、成纤维细胞的迁移等。VASP的磷酸化受PKG（cGMP-dependent protein kinase）和PKA（cAMP—dependent protein kinase）的调控。在粘附斑的形成与脱落过程中,该磷酸化起着一个“开关”的作用。本文将就近20年来VASP的研究成果,特别是近年来的进展情况做一综述。     

The role of cytoskeleton in glucose regulation

Cytoskeleton plays an important role in glucose regulation, mainly in the following three aspects. First, cytoskeleton regulates insulin secretion by guiding intracellular transport of insulin-containing vesicles and regulating release of insulin. Second, cytoskeleton is involved in insulin action by regulating distribution of insulin receptor substrate, GLUT4 translocation, and internalization of insulin receptor. In addition, cytoskeleton directs the intracellular distribution of glucose metabolism related enzymes including glycogen synthase and many glycolysis enzymes. Published in Russian in Biokhimiya, 2006, Vol. 71, No. 5, pp. 592–597.     

Acute regulation of 5′-AMP-activated protein kinase by long-chain fatty acid,glucose and insulin in rat primary adipocytes

Palmitate increased AMPK (5′-AMP-activated protein kinase) activity, glucose utilization and 2-DOG (2-deoxyglucose) transport in rat adipocytes. All three effects were blocked by the AMPK inhibitor Compound C, leading to the conclusion that in response to an increase in long-chain NEFA (non-esterified fatty acid) concentration AMPK mediated an enhancement of adipocyte glucose transport, thereby providing increased glycerol 3-phosphate for FA (fatty acid) esterification to TAG (triacylglycerol). Activation of AMPK in response to palmitate was not due to an increase in the adipocyte AMP:ATP ratio. Glucose decreased AMPK activity and effects of palmitate and glucose on AMPK activity were antagonistic. While insulin had no effect on basal AMPK activity insulin did decrease AMPK activity in the presence of palmitate and also decreased the percentage effectiveness of palmitate to increase the transport of 2-DOG. It is suggested that activation of adipocyte AMPK by NEFA, as well as decreasing the activity of hormone-sensitive lipase, could modulate adipose tissue dynamics by increasing FA esterification and, under certain circumstances, FA synthesis.     

Relationship Between Hunger-Satiety Feelings and Various Metabolic Parameters in Women with Obesity During Controlled Weight Loss

Objective : Satiety plays an important role in weight control. The meaning of fasting hormone levels and satiety feelings, and how post-absorptive changes after meals high in carbohydrate regulate appetite remains to be demonstrated. Research Methods and Procedures : Prospective metabolic study with 25 non-diabetic obese women at the Energy Metabolism Research Unit of the Department of Nutrition Sciences, University of Alabama at Birmingham. We analyzed fasting and postprandial ratings of hunger-satiety and values of various metabolic parameters (serum glucose and insulin, plasma cholecystokinin, respiratory quotient) during controlled weight loss. The postprandial measures were assessed following a test meal providing 320 kcal and yielding a food quotient of 0.89. Results : In the fasting state, there was no correlation between hunger-satiety ratings and any of the measured metabolic parameters. Under postprandial conditions, satiety was positively related to glucose (p = 0.002) and insulin (p = 0.002) responses to the test meal. In multivariate analysis including glucose, insulin, cholecystokinin, hunger-satiety ratings and respiratory quotient, insulin was the only independent predictor of satiety in the postprandial state. Discussion : These data suggest an association between the endogenous insulin response and feelings of postprandial satiety. Insulin's satiation properties, which could well be mediated by other hormones, may represent a primary factor of food intake regulation after meals relatively high in carbohydrate.     

Stimulation of Immunoreactive Insulin Release by Glucose in Rat Brain Synaptosomes

The effect of glucose on the release of immunoreactive insulin (IRI) in synaptosomes isolated from rat brain was studied. In the absence of glucose synaptosomes release about 4% (0.77 IU/mg protein) of total content. Glucose increases significantly the IRI released by synaptosomes. Addition of the glycolytic inhibitor iodoacetic acid (IAA), decreased the glucose-induced release of IRI by about 50%, suggesting that glucose metabolism is involved. The observation that glucose provides a concentration related signal for IRI release indicates that this synaptosomal preparation may be useful as a model for research on the mechanism of insulin release in brain.     

高糖高胰岛素对去甲肾上腺素诱导的心肌细胞肥大的影响

目的:利用体外培养的乳鼠心肌细胞,观测高浓度胰岛素和高浓度葡萄糖作用下对去甲肾上腺素诱导的心肌细胞肥大的影响,并探讨其可能作用机制.方法:以培养的乳鼠心肌细胞为模型分组给药后,用显微镜目镜计数心肌细胞搏动的频率;用Lowrys法测心肌细胞的蛋白质含量;用消化分离法,利用计算机图象分析系统测心肌细胞的体积;用[3H]leucine标记法测定心肌细胞蛋白的合成.结果:与对照组相比,去甲肾上腺素(NE)组、高糖组、高胰岛素组心肌细胞蛋白含量、体积、蛋白合成均有明显增加,而与高糖加NE组和高糖高胰岛素组相比较,高糖高胰岛素加NE组心肌细胞蛋白含量、体积、蛋白合成增加则更为显著.结论:单纯高浓度胰岛素培养可促进心肌细胞肥大,同时用高糖高胰岛素联合培养,可使去甲肾上腺素诱导的心肌细胞肥大作用进一步增强.