Stokes J B, Ingram M J, Williams A D, Ingram D
Kidney Int. 1981 Sep;20(3):340-7. doi: 10.1038/ki.1981.144.
This study was designed to examine the sodium, potassium, and chloride transport rates across the cortical and outer medullary collecting tubule and to localize the action of mineralocorticoid hormone. Rabbit collecting tubules were dissected from the cortex (CCT), the outer stripe of the outer medulla (OMCT0), or the inner stripe of the outer medulla (OMCTi). From normal rabbits, the transepithelial voltage was -20.8 +/- 2.7 mV in CCT, -4.2 +/- 1.4 mV in OMCT0, and +10.6 +/- 2.3 mV in OMCTi. From DOCA-treated rabbits, only the CCT voltage was different (-42.9 mV). Net sodium absorption across the CCT increased ith DOCA-treatment from 23 +/- 5 to 54 +/- 8 pEq . mm-1 . min-1, whereas net potassium secretion increased from 15 +/- 2 to 43 +/- 5 pEq . min-1 . min-1. Net chloride absorption was significant only in DOCA-treated rabbits. The OMCTi, in contrast, displayed no net transport of sodium, potassium, or chloride and had a lower rate coefficient for sodium efflux than did the CCT. DOCA treatment had no effect on any transport rate measured in this segment. The OMCT0 has small potassium secretion, which did not increase with DOCA treatment. The collecting tubule is heterogeneous along its length with respect to ion transport. Mineralocorticoid-hormone-sensitive sodium absorption is present predominantly, if not exclusively, in the cortical collecting tubule.
本研究旨在检测钠、钾和氯跨皮质和外髓集合管的转运速率，并确定盐皮质激素的作用部位。从兔的皮质（CCT）、外髓外带（OMCT0）或外髓内带（OMCTi）分离出集合管。正常兔的CCT跨上皮电压为-20.8±2.7 mV，OMCT0为-4.2±1.4 mV，OMCTi为+10.6±2.3 mV。经去氧皮质酮（DOCA）处理的兔，只有CCT的电压发生了变化（-42.9 mV）。DOCA处理后，CCT的钠净吸收量从23±5增加到54±8 pEq·mm-1·min-1，而钾净分泌量从15±2增加到43±5 pEq·min-1·min-1。氯净吸收仅在DOCA处理的兔中显著。相比之下，OMCTi没有钠、钾或氯的净转运，其钠外流速率系数低于CCT。DOCA处理对该节段测量的任何转运速率均无影响。OMCT0有少量钾分泌，DOCA处理后未增加。集合管在离子转运方面沿其长度是异质性的。盐皮质激素敏感的钠吸收主要（如果不是唯一的话）存在于皮质集合管中。
