1. The effect of modifying potassium intake on arterial plasma renin activity, angiotensin II and aldosterone concentrations, renal blood flow and their responses to exogenous angiotensin II has been assessed in twenty-six normal subjects.
2. Reduced potassium intake was associated with a significant increase in circulating renin activity and angiotensin II concentration and a significant reduction in renal blood flow. Conversely, a high potassium intake was associated with a significant increase in plasma aldosterone concentration and renal blood flow without alteration in plasma renin activity or angiotensin II concentration.
3. Reduced potassium intake decreased both the renal vascular and the adrenal response to infused angiotensin II. Conversely, an increased potassium intake enhanced the responsiveness of both systems.
4. The results suggest an important influence of potassium-induced renin-angiotensin system responses on both the renal vasculature and adrenal glomerulosa cell in normal man.