AJP - Regulatory, Integrative and Comparative Physiology, Vol 238, Issue 5 359-R363, Copyright © 1980 by American Physiological Society
Role of the renin-angiotensin system in potassium control
D. B. Young and R. E. McCaa
To determine the importance of the renin-angiotensin system in control of
plasma potassium concentration and excretion, potassium control was studied
in two groups of dogs in response to a 20-fold increase in sodium intake
(from 10 to 200 meq/day). Group I was intact whereas group II lacked
feedback control of the renin-angiotensin system, which was eliminated by
continuous infusion of 10 ng . kg-1 . min-1 angiotensin II. This rate of
infusion reduced endogenous plasma renin activity (PRA) to undetectable
levels throughout the study. The sodium forcing did not result in
measurable changes in plasma potassium concentration or excretion in group
I, in which PRA fell to 40% and plasma aldosterone concentration (PAC) to
60% of the low sodium levels. In group II the same sodium forcing produced
a 12% decrease in plasma potassium concentration and a 79% increase in
urinary potassium excretion. PAC also fell to 60% of the low sodium level
in group II. The results demonstrate the importance of the
renin-angiotensin system as a link between the nephron and the zona
glomerulosa that is essential in controlling plasma potassium concentration
and excretion during changes in sodium balance.
