Bresler E H, Nielsen K T, Miller M C, Stoud M R
Am J Physiol. 1976 Aug;231(2):642-9. doi: 10.1152/ajplegacy.1976.231.2.642.
Renal tubular reabsorptive response to rapid infusions of isotonic saline and 5% NaCl solutions were measured during brisk ethacrynic acid diuresis in anesthetized dogs. When adjustments were made for effects of variations in volume expansion, as indexed by plasma protein concentration ([Pprot]), tubular reabsorption of sodium per unit filtrate volume (TNa/GFR) was found to be significantly and positively correlated with plasma sodium concentration ([PNa]) despite hypernatremia and total body surfeit of sodium. The proportions of sodium and water reabsorbed were also homeostatically inappropriate, since the sodium concentration in the reabsorbate was somewhat in excess of that in contemporary plasma ultrafiltrate. These findings signify that glomerulotubular balance holds when the filtered load of sodium is increased by an increment in [pNa] as well as GFR. It is proposed that the moiety of tubular reabsorption (some 75% of GFR) studied here is more closely related to regulation of volume than of osmolality of sodium concentration, and the primary regulation exerted is on tubular volume reabsorption (bulk fluid reabsorption) rather than on the amount of sodium reabsorbed.
在麻醉犬进行速尿强力利尿期间，测定了肾小管对快速输注等渗盐水和5%氯化钠溶液的重吸收反应。当根据血浆蛋白浓度（[Pprot]）所反映的容量扩张变化的影响进行调整时，尽管存在高钠血症和体内钠过量，但发现单位滤液量的钠肾小管重吸收（TNa/GFR）与血浆钠浓度（[PNa]）显著正相关。重吸收的钠和水的比例在稳态方面也是不适当的，因为重吸收液中的钠浓度略高于同期血浆超滤液中的钠浓度。这些发现表明，当钠的滤过负荷因[PNa]以及肾小球滤过率（GFR）的增加而增加时，球管平衡依然存在。有人提出，此处所研究的肾小管重吸收部分（约占GFR的75%）与容量调节的关系比与钠浓度渗透压调节的关系更为密切，并且所施加的主要调节作用于肾小管容量重吸收（大量液体重吸收）而非钠重吸收量。
