Lack of prolonged effect of antidiuretic hormone on the renin-aldosterone system in the dog.

1. The effects of maximally antidiuretic, subpressor antidiuretic hormone (ADH) administration of the renin-aldosterone system were studied in dogs during 4 days of continuous intravenous infusion of ADH at a rate of 0.067 mU/kg per min. Water intake was limited to 700 ml/day to avoid changes in fluid volume status. 2. At the conclusion of the four-day study, plasma sodium concentration had fallen from 140.3 +/- 0.8 to 137.2 +/- 2.0 mmol/l, plasma potassium concentration, 22Na space, and mean arterial pressure remained within the control ranges. 3. Neither plasma renin activity nor plasma aldosterone concentration showed any tendency to change in response to the ADH infusion. 4. The results indicate that physiological levels of ADH have no prolonged, direct effect on the renin-aldosterone system.