A comparison of ascorbate and glucose transport in the heart.
A comparison of ascorbate and glucose transport in the heart.
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心脏中抗坏血酸和葡萄糖转运的比较。
DOI：
10.1152/ajpheart.1985.249.1.h141
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Reneman,RS
中科院分区：
文献类型：
--
作者：
Bassingthwaighte,JB;Kuikka,JT;Chan,IS;Arts,T;Reneman,RS
用多指示剂稀释法比较了L-[14C]抗坏血酸和D-[~3H]葡萄糖(血管内参照物~(131)I-白蛋白)在林格灌流(5 mM葡萄糖)兔心脏中的跨毛细管交换。两者的指示剂-稀释曲线在前40-80个S之间几乎重叠，毛细血管通透性-表面积乘积Psc的估计值相同，为2.3+/-0.7(SD)m l×g-1×min-1(n=18)，与它们瞬时提取的结果一致。葡萄糖和抗坏血酸的通透性相似的原因是分子质量和被动扩散率相似，它们的疏脂性，以及载体介导的内皮运输对这两种分子都很少。数据通过由空间分布的毛细血管-组织单位(毛细血管、间质、心肌细胞)的聚集体组成的模型进行分析，该模型考虑了区域血流的异质性。该制剂的间质体积增大，为0.30+/-0.04ml/g，大量进入心肌细胞，抗坏血酸和葡萄糖的细胞通透性表面积积约为2-3mlXg-1×min-1。估计的间质和细胞内空间体积分别为0.30和0.47mlXg-1Xmin-1，反映了间质水肿，与测量值非常接近，从而保证了建模分析的方法。
Multiple indicator-dilution experiments were done to compare the transcapillary exchange of tracer amounts of L-[14C]ascorbate and D-[3H]glucose (against an intravascular reference 131I-albumin) in Ringer-perfused (5 mM glucose) isolated rabbit hearts. The indicator-dilution curves for the two were virtually superimposed over the first 40-80 s. Estimates of the capillary permeability-surface area products, PSc, were the same, 2.3 +/- 0.7 (SD) ml X g-1 X min-1 (n = 18), in accord with the coincidence of their instantaneous extractions. The similarity of glucose and ascorbate permeabilities is explained by the similarity in molecular weights and passive diffusivity, their lipophobic nature, and the paucity of carrier-mediated endothelial transport for either molecule. The data were analyzed via a model composed of aggregates of spatially distributed capillary-tissue units (capillary blood, interstitium, myocytes) accounting for the heterogeneity of regional flows. The interstitial volumes in this preparation are enlarged, 0.30 +/- 0.04 ml/g. There is substantial entry into myocardial cells, the cell permeability-surface area products being approximately 2-3 ml X g-1 X min-1 for ascorbate and glucose. The estimated volumes of interstitial and intracellular space, 0.30 and 0.47 ml X g-1 X min-1, reflect interstitial edema and are very close to measured values, giving reassurance concerning the methods of modeling analysis.