AJP - Renal Physiology, Vol 232, Issue 4 298-F306, Copyright © 1977 by American Physiological Society
Stimulation of renal sodium reabsorption by angiotensin II
M. D. Johnson and R. L. Malvin
Various parameters of renal function were studied before, during, and after
the infusion of physiological increments of angiotensin II directly into
one renal artery of anesthetized dogs. During water diuresis and during
antidiuresis induced with exogenous antidiuretic hormone (ADH), angiotensin
II consistently reduced UNaV, UKV, and CPAH, and increased the filtration
fraction in the infused kidney. Urinary osmolality was increased only in
the presence of ADH, while during water diuresis angiotensin II had no
apparent effect on urinary osmolality or flow rate. During saline diuresis,
a mean increment of angiotensin II concentration of 14 pg/ml was sufficient
to significantly reduce UNaV and urinary flow rate. Changes in CCr, CPAH,
and filtration fraction did not correlate with changes in sodium excretion,
and intracortical distribution of blood flow remained unaltered. These data
support the hypothesis that normal circulating levels of angiogensin II
play a direct renal role in the control of sodium, potassium, and water
homeostasis, and that angiotensin II exerts a direct, stimulatory effect on
tubular sodium reabsorption independent of changes in GFR, RPF, filtration
fraction, or intracortical distribution of blood flow.
