AJP - Renal Physiology, Vol 252, Issue 6 1048-F1054, Copyright © 1987 by American Physiological Society
Aldosterone is a physiologically significant kaliuretic hormone
W. R. Adam, A. G. Ellis and B. A. Adams
To study the role of aldosterone in the short-term control of potassium
excretion, rats were gavaged with a liquid diet containing 10-20% of their
daily caloric and potassium intake, with a range of sodium intakes. Levels
of (effective) aldosterone at the time of gavage were manipulated by
administration of spironolactone, aldosterone, and adrenalectomy. Urinary
sodium, potassium, and creatinine excretion were measured in conscious
unrestrained rats for 2 h after the food load, and then blood was collected
for measurement of plasma potassium, aldosterone, and renin activity.
Potassium excretion was dependent on both dietary potassium and a minimum
dietary sodium content. Potassium excretion was reduced by spironolactone
and adrenalectomy and increased by acute aldosterone treatment in most
dietary groups. These results strongly suggest that the ambient levels of
aldosterone are important in determining potassium excretion following food
ingestion. Plasma aldosterone was higher with the higher potassium and
lower sodium content diets. Changes in plasma aldosterone, with variations
in dietary potassium or sodium, suggest a role for aldosterone in
subsequent potassium excretion.
