title: Urate reabsorption in proximal convoluted tubule of the rat kidney.
abstract: 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.
mesh_terms: D000818:Animals; D002740:Chlorothiazide / Q000494:pharmacology; D004039:Diet, Sodium-Restricted; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006400:Hematocrit; D006852:Hydrochlorothiazide / Q000494:pharmacology; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D008297:Male; D051381:Rats; D012964:Sodium / Q000652:urine; D014527:Uric Acid / Q000378:metabolism* / Q000652:urine; D014867:Water / Q000378:metabolism
chemical_list: D014867:Water; D006852:Hydrochlorothiazide; D014527:Uric Acid; D002740:Chlorothiazide; D012964:Sodium