Characteristics of urea transport of cells derived from rabbit thick ascending limb of Henle's loop
Characteristics of urea transport of cells derived from rabbit thick ascending limb of Henle's loop
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DOI：
10.1046/j.1523-1755.1998.00980.x
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发表时间：
1998-07-01
影响因子：
19.6
通讯作者：
Müller, GA
中科院分区：
文献类型：
--
作者：
Grunewald, RW;Reisse, CH;Müller, GA
背景。亨利氏袢粗升肢（TALH）被认为参与肾尿素梯度的调节。方法。我们通过密度离心和两室培养）和体积调节（阻抗测量）对来自兔外髓质的高度分化细胞的尿素摄取进行了表征。结果。暴露于 600 mOsm/升（300 mM 尿素）的 TALH 细胞收缩至等渗体积的 72 +/- 5%。由于调节体积增加 (RVI)，五分钟后细胞体积几乎完全恢复到 92 +/- 6%。在尿素浓度高达 600 mM 的情况下，C-14-尿素的吸收未显示任何饱和。在存在根皮素的情况下，尿素摄取量下降至 69 +/- 14%。运输与钠和氯无关。改变膜电位导致调节体积增加和尿素吸收增加。蔗糖 (300 mM) 和 NaCl (150 mM) 诱导的高渗透压导致尿素摄取分别减少至 70 +/- 14% 和 53 +/- 11%。两室培养物中的渗透系数(P)为P=1.7×10(-6)+/-0.39。 10(-6) cm/秒，表明渗透性相对较低。结论。由于低渗透性：TALH 在肾单位内的尿素循环中实现生理上显着的参与似乎是不可能的。然而，这项研究的结果提供了关于特定尿素转运机制存在的重要提示，该机制使细胞能够快速适应不同的渗透压。
Background. The thick ascending limb of Henle's loop (TALH) is thought to be involved in the regulation of the renal urea gradient.Methods. We have characterized the uptake of urea toil density centrifugation and 2-compartment-culture) and volume regulation (impedance measurement) in highly differentiated cells derived from rabbit outer medulla.Results. TALH cells exposed to 600 mOsm/liter (300 mM urea) shrunk to 72 +/- 5% of the isoosmotic volume. Due to a regulatory volume increase (RVI), the cell volume was almost completely regained at 92 +/- 6% after five minutes. The uptake of C-14-urea in the presence of urea concentrations up to 600 mM did not show any saturation. In the presence of phloretin the urea uptake decreased to 69 +/- 14%. The transport was sodium and chloride independent. Changing the membrane potential caused an increase of regulatory volume increase and urea uptake. Hyperosmolarity induced by sucrose (300 mM) and NaCl (150 mM) caused a decrease of urea uptake to 70 +/- 14% and 53 +/- 11%, respectively. The permeability coefficient (P) in a two compartment culture was P = 1.7 10(-6) +/- 0.39 . 10(-6) cm/second, suggesting a relatively low permeability.Conclusion. Due to the low permeability: it seems impossible to achieve a physiologically significant participation of the TALH in the urea circulation within the nephron. However, the results of this study provides significant hints about the existence of a specific urea transport mechanism that enables the cell to adapt rapidly to different osmolarities.