Dixon B S, Dillingham M A, Anderson R J
Department of Medicine, University of Colorado Health Sciences Center, Denver 80262.
J Lab Clin Med. 1987 Oct;110(4):454-9.
Flow rate dependence of both electrolyte and nonelectrolyte transport in various nephron segments has been described. Prior studies have used relatively leaky epithelia in which the flow rate-dependent transport phenomena can be explained in terms of alterations in axial and radial concentration profiles. In this study, the flow rate dependence of either vasopressin or cyclic adenosine monophosphate-stimulated water flux (Jv), hydraulic conductivity (Lp), and osmotic permeability (Pf) were measured in isolated perfused rabbit cortical collecting tubules. Increasing perfusion rate from 6.0 +/- 0.4 to 20.7 +/- 1.2 nl/min results in highly significant increases in Jv (131%) and in Lp and Pf (120%). In this relatively tight epithelium, osmotic equilibrium did not occur. Although the mechanism of this effect remains to be elucidated, the present results mandate maintenance of constant flow rates when examining the perfused cortical collecting tubular response to vasopressin.
已经描述了不同肾单位节段中电解质和非电解质转运的流速依赖性。先前的研究使用了相对渗漏的上皮细胞，其中流速依赖性转运现象可以根据轴向和径向浓度分布的变化来解释。在本研究中，在分离灌注的兔皮质集合管中测量了抗利尿激素或环磷酸腺苷刺激的水通量（Jv）、水力传导率（Lp）和渗透渗透率（Pf）的流速依赖性。灌注速率从6.0±0.4 nl/min增加到20.7±1.2 nl/min会导致Jv（131%）以及Lp和Pf（120%）显著增加。在这种相对紧密的上皮细胞中，未发生渗透平衡。尽管这种效应的机制仍有待阐明，但目前的结果要求在检查灌注的皮质集合管对抗利尿激素的反应时保持恒定的流速。
