Angiotensin II: a candidate for an aldosterone-independent mediator of potassium preservation during volume depletion.

Two different stimulators of aldosterone secretion, high-potassium diet and low-sodium diet, have disparate effects on potassium secretion in the distal nephron. The mechanism by which the kidney preserves potassium in the face of a high-aldosterone, volume-depleted state has engendered much thought. Yue et al. now propose that angiotensin II inhibits the renal outer medullary potassium channel (ROMK1) through stimulation of the protein tyrosine kinase c-Src, perhaps acting as a signal to differentiate volume depletion from a high-potassium diet.