Molecular sieving of albumin by the ascending vasa recta wall.
Molecular sieving of albumin by the ascending vasa recta wall.
复制标题
直肠升血管壁对白蛋白进行分子筛分。
DOI：
10.1172/jci115852
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Pallone,TL
中科院分区：
文献类型：
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作者：
Pallone,TL
升直小血管对白蛋白的分子筛选。存在证据支持肾髓质中存在血管外白蛋白池。本研究采用活体微灌注技术测量125 I标记的白蛋白从下行和上行直血管到乳头状血管的转运。在呋塞米利尿期间，使用含有FITC标记的葡聚糖（FITC-Dx）2 x 10（6）mol wt和125 I-白蛋白的缓冲液进行灌注。调整灌注液白蛋白和收集压力，以诱导零跨毛细血管体积流量（Jv）或高体积流量。当Jv为0时，DVR和AVR中FITC-Dx（RDX）和125 I-白蛋白（Ralb）的收集液与灌注液比率相同，这意味着白蛋白的扩散流出量非常小。相反，当Jv增加时，同一AVR中Ralb和RDX的配对比较显示差异，分别为1.58 +/- 0.06 vs 1.72 +/- 0.08（P <0.01）。水缺乏动物的AVR灌注显示出相似的结果，Ralb = 1.70 +/- 0.07和RDX = 2.00 +/- 0.07（P小于0.01）。这些数据表明，白蛋白在体内通过直小血管的转运可能是由溶剂阻力。AVR壁对125 I-白蛋白的反射系数估计为0.78。
Molecular sieving of albumin by ascending vasa recta. Evidence exists to support the presence of an extravascular pool of albumin in the renal medullary interstitium. This study used microperfusion in vivo to measure the transport of 125I-labeled albumin from descending (DVR) and ascending vasa recta (AVR) to the papillary interstitium. Perfusions were performed during furosemide diuresis with a buffer containing FITC-labeled dextran (FITC-Dx) 2 x 10(6) mol wt and 125I-albumin. Perfusate albumin and collection pressure were adjusted to induce either zero transcapillary volume flux (Jv) or high volume flux. When Jv was zero, the collectate-to-perfusate ratios of FITC-Dx (RDX) and 125I-albumin (Ralb) in the DVR and AVR were identical implying that diffusive efflux of albumin was immeasurably small. In contrast, when Jv was increased, paired comparison of Ralb and RDX in the same AVR revealed a difference, 1.58 +/- 0.06 vs 1.72 +/- 0.08, respectively (P less than 0.01). AVR perfusions in hydropenic animals showed similar results, Ralb = 1.70 +/- 0.07 and RDX = 2.00 +/- 0.07 (P less than 0.01). These data suggest that albumin transport across vasa recta in vivo is likely to be governed by solvent drag. The reflection coefficient of the AVR wall to 125I-albumin is estimated to be 0.78.