Effects of a novel KATP channel blocker on renal tubule function and K channel activity.

ATP-sensitive potassium channels (KATP) modulate Na, K and Cl reabsorption in the thick ascending limb of the loop of Henle and K secretion in the cortical collecting tubule. Inhibition of potassium recycling in the apical membrane of the thick ascending limb of the loop of Henle interferes with sodium reabsorption and suppression of the apical potassium conductance in principal cells of the cortical collecting tubule and reduces potassium secretion. Both potassium recycling and potassium secretion depend critically on the activity of KATP, and recent studies indicate that the sulfonylurea compound glyburide, a known KATP channel blocker, is diuretic but does not produce kaliuresis.