Dose-dependent reduction in renal magnesium clearance by amiloride during frusemide-induced diuresis in rats

The effects of the potassium-sparing diuretic, amiloride, on fractional magnesium excretion were investigated at four doses (0.02, 0.08, 0.20 and 2.00 mg kg-1 h-1) during frusemide-induced diuresis. Amiloride caused a dose-dependent reduction in the fractional excretion of both magnesium and potassium, whereas the effects of amiloride, over the same dose range, on fractional sodium and calcium excretion were not dose-dependent. The results indicate that amiloride exerted a specific renal action to alter magnesium and potassium transport dissociated from effects on sodium excretion.