Studies on Aldosterone Responsiveness to Angiotensin II during Clinical Variations in Calcium Metabolism in Normal Man

1. Angiotensin II was infused at stepwise increasing dose rates (2, 4 and 10 pmol min^–1 kg^–1) in 12 normal subjects. Infusions were performed in the presence of normocalcaemia, mild hypercalcemia induced by concomitant calcium gluconate infusion, and after 2 weeks of treatment with nifedipine.

2. Pre-infusion plasma levels of angiotensin II, renin or aldosterone were not altered by acute mild hypercalcaemia or administration of nifedipine. The angiotensin II-induced increases in plasma aldosterone were also similar under the three study conditions.

3. Variations in calcium metabolism occurring under clinical conditions appear to play a minor role in modulating the angiotensin II-dependent pathway of aldosterone regulation in normal man.