The Ontogeny of Sugar Transport in Kidney
The Ontogeny of Sugar Transport in Kidney
复制标题
肾脏糖运输的个体发育
DOI：
10.1203/00006450-197812000-00005
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发表时间：
1978
影响因子：
3.6
通讯作者：
S. Segal
中科院分区：
文献类型：
--
作者：
K. Roth;S. Hwang;M. Yudkoff;S. Segal
总结：已证明新生Sprague-Dawley大鼠的分离肾小管碎片对α-甲基-D-葡萄糖苷（AMG）的集中摄取，并通过新生肾皮质对AMG摄取的体内证明证实了该现象的有效性。新生儿肾小管中的进入现象的动力学分析揭示了AMG存在两种不同的膜转运系统，其中只有一种存在于成人肾小管中。所有运输的糖在新生儿和成人肾小管根皮苷敏感，但只有部分抑制在Na+-无缓冲液。葡萄糖显示出在共享的高容量系统上竞争性地抑制摄取。新生儿对高亲和力系统的摄取占生理糖浓度下总摄取的15-20%。由此得出结论，活跃的糖转运是新生大鼠肾脏的一个特征，并且离体小管制备物比肾皮质切片更准确地反映了这一现象。除了在成人中也发现的较低亲和力系统之外，新生儿肾小管中独特的高亲和力葡萄糖转运系统的存在使得解剖学上未成熟的肾脏能够有效地从肾脏中回收糖。肾小球滤液，从而防止在促进生长过程中损失有价值的热量营养素。
Summary: Concentrative uptake of α-methyl-D-glucoside (AMG) by isolated renal tubule fragments from the newborn Sprague-Dawley rat has been demonstrated and the validity of this phenomenon confirmed by an in vivo demonstration of AMG uptake by the newborn kidney cortex. A kinetic analysis of the entry phenomenon in the newborn tubule reveals the presence of two distinct membrane transport systems for AMG, only one of which is present in the adult tubule. All transport of sugar in both newborn and adult tubules was phlorizin-sensitive, but was only partially inhibited in Na+-free buffer. Glucose was shown to inhibit uptake competitively on the shared, high capacity system. Uptake on the high affinity system in the newborn represents 15-20% of the total at physiologic sugar concentrations. It is concluded that active sugar transport is a characteristic of the newborn rat kidney and that the isolated tubule preparation is a more accurate reflection of this phenomenon than is the renal cortical slice.Speculation: The presence of a unique high affinity glucose transport system in newborn renal tubules in addition to the lower affinity system also found in the adult enables the anatomically immature kidney to efficiently reclaim sugar from the glomerular filtrate and, thus, to prevent loss of calorically valuable nutrients in the promotion of growth.