MICROPUNCTURE STUDY OF WATER ELECTROLYTES AND UREA MOVEMENTS ALONG LOOPS OF HENLE IN PSAMMOMYS
MICROPUNCTURE STUDY OF WATER ELECTROLYTES AND UREA MOVEMENTS ALONG LOOPS OF HENLE IN PSAMMOMYS
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DOI：
10.1172/jci106005
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发表时间：
1969-01-01
影响因子：
15.9
通讯作者：
MOREL, F
中科院分区：
文献类型：
--
作者：
DEROUFFIGNAC, C;MOREL, F
本文研究了在盐性利尿的条件下，肾小管液沿着Henle袢降支渗透压增高的机制。在两个系列的实验中，从皮质表面的近端和远端回旋处，或从Henle环和乳头的肾外部分的表面处的集合管处收集微穿刺样品。在所有微穿刺样品中测定菊粉-3 H、尿素-14 C、Na+和K+浓度以及渗透压。通过比较从曲小管和Henle袢获得的菊粉数据，因为表面肾小球的滤过率似乎有很大的差异（9 nl/min）和深层结果表明，在这些实验条件下，水的净运动沿着环路不发生，仅为23%（21.4 nl/min）滤液的沿着Henle袢被重吸收B）早期远端样本中的（F/P）Inin与尿液的同时渗透压之间没有正相关; c）当（F/P）In-Osmin环样品与（F/P）Osmin环样品相关时，菊粉浓度的增加仅占渗透压增加的15%。因此，沿着下降分支发生的85%的浓缩过程一定是由溶质的净添加引起的;这直接得到了环样品中Na+和K+测量值的支持，该测量值表明，在环的尖端，Na+和K+流速与渗透压相关。此外，由于Na ~+-尿素流率在浅早期远端小管中的负荷是恒定的，并且与尿渗透压无关，因此提示在升支和降支之间存在着一种髓循环。输送到远端表浅小管的平均K+是其过滤速率的4.18倍，表明尿素从集合管再循环到亨利氏袢。薄的下降肢的壁的渗透率特性进行了讨论，在所获得的结果。
The mechanism by which the osmotic pressure increases in tubular fluid along the descending limb of the loop of Henle was examined inPsammomysundergoing salt diuresis. In two series of experiments, micropuncture samples were collected either from proximal and distal convolutions at the surface of the cortex, or from loops of Henle and collecting ducts at the surface of the extrarenal part of the papilla. Inulin-3H, urea-14C, Na+, and K+concentrations, as well as osmotic pressure, were determined in all micropuncture samples.Net movements of water along the descending and ascending limbs of the loop could not be deduced by comparing inulin data obtained from convoluted tubules and from loops of Henle, since there appeared to be a large difference in the filtration rate of the superficial glomeruli (9 nl/min) and the deep ones (21.4 nl/min) under the conditions of these experiments.The results indicate that no large net movement of water occurred along the loop sincea) only 23% of the filtrate was reabsorbed along the loop of Henle (including pars recta) of superficial nephrons despite the fact that all these loops reached markedly hypertonic regions;b) there was no positive correlation between (F/P)Inin early distal samples and the simultaneous osmotic pressure of the urine;c) when (F/P)Inand (F/P)Osmin loop samples were correlated, the increase in inulin concentration accounted only for 15% of the increase in osmotic pressure. Therefore, 85% of the concentrating process taking place along the descending limb must have resulted from net addition of solutes; this was directly supported by Na+and K+measurements in the loop samples, which showed that, at the tip of the loops, the Na+and K+flow rates were correlated to the osmotic pressure. Moreover, since the load of Na+urea flow rate in superficial early distal tubules was constant and independent of the urinary osmotic pressure, it is suggested that a medullary recycling of both ions occurred between ascending and descending limbs.Urea-14C concentration in the loop samples indicates a net addition of urea into the descending limb; the mean and K+delivered to the distal superficial tubules was 4.18 times its filtration rate, suggesting a recycling of urea from collecting ducts to Henle's loops. The permeability properties of the wall of the thin descending limb are discussed in relation to the obtained results.