Wong P Y, Au C L, Ngai H K
Jpn J Physiol. 1980;30(1):1-15. doi: 10.2170/jjphysiol.30.1.
Electrolytes and water transport have been studied in the perfused isolated duct of the rat cauda epididymis in vitro. The rates of reabsorption of sodium, chloride and water and of secretion of potassium were found to be comparable to those in the perfused rat cauda epididymidis in vivo. Sodium reabsorption was isotonic and inhibited by the metabolic uncoupler 2,4-dinitrophenol and cooling. Removal of sodium ions from the intraluminal fluid abolished water reabsorption in the isolated duct. When potassium ions were removed from the peritubular medium the secretion of potassium was abolished, but the reabsorption of sodium and water was unaffected. Under this condition, the reabsorption of chloride was enhanced. Removal of calcium ions from the lumen increased the rates of sodium and water reabsorption and potassium secretion by twofold. Amiloride (10(-4) M) added to the intraluminal fluid had no effect on the electrolyte and water transport in the isolated duct, whereas triaminopyrimidine produced a dose-dependent inhibition of sodium and water reabsorption when added to both sides. Sodium and water reabsorption were found to be inhibited by the application of ouabain (10(-3) M) to the peritubular side and of ethacrynic acid (10(-4) to 10(-5) M) to the luminal peritubular side and of ethacrynic acid (10(-4) to 10(-5) M) to the luminal side. These results are discussed in the light of the recent concepts of isosmotic transepithelial transport.
已在体外对大鼠附睾尾的灌注离体管道中的电解质和水转运进行了研究。发现钠、氯和水的重吸收率以及钾的分泌率与体内灌注的大鼠附睾尾中的情况相当。钠重吸收是等渗的，并且受到代谢解偶联剂2,4 -二硝基苯酚和冷却的抑制。从管腔内液中去除钠离子会消除离体管道中的水重吸收。当从肾小管周介质中去除钾离子时，钾分泌被消除，但钠和水的重吸收不受影响。在这种情况下，氯的重吸收增强。从管腔中去除钙离子使钠和水的重吸收率以及钾分泌率提高了两倍。向管腔内液中添加氨氯吡脒（10(-4) M）对离体管道中的电解质和水转运没有影响，而当向两侧添加三氨嘧啶时，会产生剂量依赖性的钠和水重吸收抑制作用。发现向肾小管周侧施加哇巴因（10(-3) M）以及向管腔侧和肾小管周侧施加依他尼酸（10(-4)至10(-5) M）会抑制钠和水的重吸收。根据等渗跨上皮转运的最新概念对这些结果进行了讨论。
