Computer analysis reveals changes in renal Na+-glucose cotransporter in diabetic rats.
Computer analysis reveals changes in renal Na+-glucose cotransporter in diabetic rats.
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计算机分析揭示了糖尿病大鼠肾钠-葡萄糖协同转运蛋白的变化。
DOI：
10.1152/ajpcell.1989.257.2.c385
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
D. Diedrich
中科院分区：
文献类型：
--
作者：
M. Blank;F. Bode;K. Baumann;D. Diedrich
开发了一种新的计算机辅助程序来分析大鼠肾皮质刷边膜囊（BBMV） Na+-葡萄糖共运输的时间过程。转运体特性可以测量，常规的动力学分析无法区分：共转运体膜密度来源于每毫克蛋白质结合的d -葡萄糖的皮摩尔。结合是立体特异性的，被根际菌素阻断，并被Na+或K+（但不包括Cs+）同样支持。复合Na+驱动的内流和（假定的）Na+独立的外排过程的准一级内流和外排速率常数高度依赖于葡萄糖浓度。当葡萄糖降至低水平时，近端小管中存在两种Na+-葡萄糖转运蛋白或单一机制突然改变速率。主要工作方式缓慢，具有高容量但低亲和力，并且可能具有2na +:2葡萄糖化学计量（Hill系数为单位）。小系统是一个快速、小容量、高亲和力的操作，具有2 Na+:1葡萄糖化学计量，当在传统的动力学图中分析相同的数据时，无法区分。用链脲佐菌素诱导的糖尿病大鼠实验结果说明了该方法的实用性。低糖亲和性共转运蛋白在高血糖动物中上调，但在病毒质、酮症酸中毒动物中没有上调。糖尿病患者的速率常数，尤其是外排速率常数降低。
A novel, computer-assisted program was developed to analyze the time course of Na+-glucose cotransport by rat renal cortical brush-border membrane vesicles (BBMV). Transporter characteristics can be measured, which routine kinetic analyses fail to distinguish: cotransporter membrane density is derived from the picomoles of D-glucose bound per milligram of protein. Binding is stereospecific, blocked by phlorizin, and supported equally well by Na+ or K+ (but not Cs+). Quasi-first-order influx and efflux rate constants for the composite Na+-driven influx and the (presumed) Na+-independent efflux processes were highly dependent on glucose concentration. Either two Na+-glucose transporters exist in proximal tubules or a single mechanism abruptly changes rate when glucose falls to low levels. The major operation mode is slow, has a high capacity but low affinity, and may have a 2 Na+:2 glucose stoichiometry (Hill coefficient is unity). The minor system is a fast, smaller-capacity, higher-affinity operation with a 2 Na+:1 glucose stoichiometry that was not distinguishable when the same data were analyzed in conventional kinetic plots. Results with streptozocin-induced diabetic rats illustrate the method's utility. Low-glucose-affinity cotransporters were upregulated in hyperglycemic, but not in cachectic, ketoacidotic animals. Rate constants, especially for efflux, were decreased in diabetes.
DOI：
10.1016/0005-2736(84)90253-0
发表时间：
1984-01-01
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA
影响因子：
--
作者：
HEINZ, E;WEINSTEIN, AM
通讯作者：
WEINSTEIN, AM
大鼠肾近曲小管中的葡萄糖转运和代谢：胰岛素的多组分效应。
DOI：
10.1016/0005-2736(86)90146-x
发表时间：
1986
期刊：
Biochimica et biophysica acta
影响因子：
--
作者：
Kleinzeller,A;McAvoy,EM
通讯作者：
McAvoy,EM