Failure of voltage augmentation of distal H+ secretion
When H+ ions enter the lumen of the renal tubule it will become more positive. Reabsorption of Na+ from the lumen will have the opposite effect and augment the movement of H+ into the lumen. Factors which reduce delivery of Na+ (ECF volume contraction) or inhibit reabsorption of Na+ (amiloride, trimethoprim, aldosterone deficiency or inhibition) will reduce H+ secretion.