Suzuki M, Terao N, Asano Y, Hosoda S
Department of Nephrology and Cardiology, Jichi Medical School, Kawachi-gun.
Tohoku J Exp Med. 1987 Jul;152(3):283-90. doi: 10.1620/tjem.152.283.
We have recently improved the technique of the isolated perfused rat kidney by addition of amino acids to the perfusion solution. Utilizing this improved preparation, we examined to what extent chronic acid-base status can alter H+ and/or bicarbonate transport in the whole kidney and the effect of acetazolamide (10(-4) M) on this process. Kidneys from rats that had been drinking tap water (control), 1.5% NH4Cl (acidotic), or 1.5% NaHCO3 (alkalotic) were perfused with a solution of identical pH and PCO2. During the control period, the fractional bicarbonate reabsorption was higher in acidotic rats than in control rats by 1.0% and urine pH was lower than those in control. On the other hand, the two parameters were not different between control and alkalotic rats. Acetazolamide increased urine pH and decreased the fractional bicarbonate reabsorption in all, but these parameters in acidotic and alkalotic rats were not different compared with those in control. We conclude that adaptive changes of H+ and/or bicarbonate transport in chronic metabolic acidosis corresponds to about 1.0% as fractional bicarbonate reabsorption by the isolated perfused kidney and is largely carbonic anhydrase dependent.
我们最近通过在灌注液中添加氨基酸改进了离体灌注大鼠肾脏的技术。利用这种改进的制备方法，我们研究了慢性酸碱状态在多大程度上可以改变整个肾脏中H⁺和/或碳酸氢盐的转运以及乙酰唑胺（10⁻⁴ M）对这一过程的影响。用pH值和PCO₂相同的溶液灌注来自饮用自来水（对照）、1.5%氯化铵（酸中毒）或1.5%碳酸氢钠（碱中毒）的大鼠的肾脏。在对照期，酸中毒大鼠的碳酸氢盐重吸收分数比对照大鼠高1.0%，且尿pH值低于对照大鼠。另一方面，对照大鼠和碱中毒大鼠的这两个参数没有差异。乙酰唑胺使所有大鼠的尿pH值升高，碳酸氢盐重吸收分数降低，但酸中毒和碱中毒大鼠的这些参数与对照大鼠相比没有差异。我们得出结论，慢性代谢性酸中毒时H⁺和/或碳酸氢盐转运的适应性变化相当于离体灌注肾脏中碳酸氢盐重吸收分数的约1.0%，并且在很大程度上依赖于碳酸酐酶。
