TY - JOUR T1 - Renal Effects of Glibenclamide: A Micropuncture Study JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 464 LP - 467 VL - 285 IS - 2 AU - M. A. Bailey AU - S. J. Walter Y1 - 1998/05/01 UR - http://jpet.aspetjournals.org/content/285/2/464.abstract N2 - The renal effects of glibenclamide were investigated using free flow micropuncture techniques in anesthetized Sprague-Dawley rats. Intravenous infusion of the drug (3 mg/hr) evoked a natriuresis and diuresis; potassium excretion remained unchanged. Fractional reabsorption in the proximal convoluted tubule in glibenclamide-infused rats did not differ significantly from that in control animals, although the late proximal tubular fluid to plasma concentration ratio for potassium was reduced. Fractional sodium delivery to the early distal tubule was elevated, while the fractional deliveries of water and potassium to this nephron site were unaffected. We conclude that glibenclamide impairs sodium reabsorption in one or more of the nephron segments that comprise the loop of Henle. These results are consistent with the hypothesis that the natriuresis resulting from glibenclamide administration is a consequence of blockade of potassium channels in the apical membrane of the thick ascending limb of Henleā€™s loop. The data suggest that glibenclamide may additionally inhibit a small secretory potassium flux in the proximal tubule. The American Society for Pharmacology and Experimental Therapeutics ER -