Time course of the renal functional response to partial nephrectomy: measurements in conscious rats
Time course of the renal functional response to partial nephrectomy: measurements in conscious rats
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DOI：
10.1113/expphysiol.2006.034751
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发表时间：
2007-01-01
影响因子：
2.7
通讯作者：
Shirley, D. G.
中科院分区：
文献类型：
--
作者：
Chamberlain, R. M.;Shirley, D. G.
以前的研究中，肾质量减少后存活的肾单位的功能反应主要是在麻醉动物中进行的，很少考虑到代偿性变化如何随时间发展。本研究评估了一种方法，用于确定肾小球滤过率（GFR）在不受限制的，未插管，清醒大鼠（血浆中的Tc-99 m-二乙烯三胺五乙酸（DTPA）消失），并已使用这种方法来记录GFR的变化超过32天的时间过程后，单肾切除术或5/6肾切除术。同时测量排泄率和锂的清除率（后者是近端液体输送的指标），提供了有关整体肾小管功能和节段性重吸收变化的信息。单肾切除后，剩余肾脏的GFR（与假手术动物的单肾相比）在8天内增加最大（接近50%）; 5/6肾切除后，剩余肾脏的GFR在16天内增加最大（接近300%）。在整个研究期间，部分肾切除动物的钠和钾的总排泄率保持良好，而水的排泄增加（单肾切除术后接近30%，5/6肾切除术后接近120%），部分是由于GFR的代偿性增加，但主要是由于中度（单肾切除术后）或显著（5/6肾切除术后）重吸收分数减少。在5/6肾切除术后早期，钾排泄有时超过滤过负荷，表明净分泌。锂清除率数据表明，5/6肾切除术后肾小管功能的变化包括近端小管重吸收分数的减少，而单肾切除术后，对近端小管的任何此类影响都是轻微和短暂的。
Previous investigations into the functional responses of the surviving nephrons following reductions in renal mass have been performed largely in anaesthetized animals and have taken little account of how the compensatory changes develop with time. The present study has assessed a method for determining glomerular filtration rate (GFR) in unrestrained, uncatheterized, conscious rats (plasma disappearance of Tc-99m-diethylenetriamene pentaacetic acid (DTPA)) and has used this method to document the time course of the changes in GFR over a 32 day period following uninephrectomy or 5/6 nephrectomy. Concurrent measurements of excretion rates and of the clearance of lithium (the latter being an index of end-proximal fluid delivery) provided information on changes in overall tubular function and segmental reabsorption. After uninephrectomy, the GFR of the remaining kidney (compared with that of a single kidney of sham-operated animals) increased maximally (by similar to 50%) within 8 days; after 5/6 nephrectomy, the increase in the GFR of the remnant kidney was maximal (at similar to 300%) within 16 days. Overall excretion rates of sodium and potassium were well maintained in partially nephrectomized animals throughout the period of study, while the excretion of water increased (by similar to 30% after uninephrectomy and by similar to 120% after 5/6 nephrectomy), partly as a result of the compensatory increases in GFR but mainly as a consequence of moderate (after uninephrectomy) or marked (after 5/6 nephrectomy) reductions in fractional reabsorption. During the early period after 5/6 nephrectomy, potassium excretion sometimes exceeded the filtered load, indicating net secretion. Lithium clearance data indicated that the changes in tubular function after 5/6 nephrectomy include a reduction in fractional reabsorption in the proximal tubule, whereas after uninephrectomy any such effect on the proximal tubule is minor and transient.