Weinman E J, Steplock D, Suki W N, Eknoyan G
Am J Physiol. 1976 Aug;231(2):509-15. doi: 10.1152/ajplegacy.1976.231.2.509.
Urate reabsorption was examined in the rat utilizing clearance and in vivo microperfusion techniques. In control rats, the fractional excretion of urate averaged 12.5 +/- 1.3% of the filtered load, with 60-70% of perfused urate reabsorbed at 2 mm of perfused tubule length (urate efflux). Increasing the perfusion concentration of urate to 6, 12, and 25 mg/100 ml did not alter the fractional rate of reabsorption. The acute administration of chlorothiazide resulted in a fall in GFR and Curate such that the fractional excretion was unchanged from controls and averaged 13.3 +/- 2.0%, without an associated change in urate reabsorption from proximal perfusates despite the presence of significant inhibition of sodium and water reabsorption. By contrast, the chronic administration of chlorothiazide accompanied by a low-sodium diet resulted in a significantly lower fractions excretion rate of urate of 7.95 +/- 0.5% and a significant increase in reabsorption of sodium and water as well as urate from microperfusates, In control rats receiving an infusion of 5% mannitol in isotonic saline, urate secretion was demonstrated by the urinary precession of [2-14C]urate from [methoxy-3H]inulin following placement of these isotopes on the surface of the kidney. The additional infusion of chlorothiazide did not alter this pattern of isotope recovery in the urine.
利用清除率和体内微灌注技术在大鼠中研究了尿酸重吸收情况。在对照大鼠中，尿酸的分数排泄平均为滤过负荷的12.5±1.3%，在灌注肾小管长度为2mm时，60 - 70%的灌注尿酸被重吸收（尿酸外流）。将尿酸的灌注浓度增加到6、12和25mg/100ml并没有改变重吸收的分数率。急性给予氯噻嗪导致肾小球滤过率（GFR）和尿酸清除率（Curate）下降，使得分数排泄与对照组无变化，平均为13.3±2.0%，尽管存在对钠和水重吸收的显著抑制，但近端灌注液中尿酸重吸收没有相关变化。相比之下，慢性给予氯噻嗪并伴有低钠饮食导致尿酸的分数排泄率显著降低，为7.95±0.5%，并且从微灌注液中重吸收的钠、水以及尿酸显著增加。在接受等渗盐水中5%甘露醇输注的对照大鼠中，在将[2 - 14C]尿酸和[甲氧基 - 3H]菊粉放置在肾脏表面后，通过尿液中[2 - 14C]尿酸相对于[甲氧基 - 3H]菊粉的优先出现证明了尿酸分泌。额外输注氯噻嗪并没有改变尿液中这种同位素回收模式。
