AJP - Regulatory, Integrative and Comparative Physiology, Vol 258, Issue 1 232-R239, Copyright © 1990 by American Physiological Society
ANF and postprandial control of sodium excretion in dogs with compensated heart failure
D. Villarreal, R. H. Freeman and M. W. Brands
Department of Physiology, University of Missouri School of Medicine, Columbia.
The changes in plasma immunoreactive atrial natriuretic factor (iANF) and
urinary Na excretion that occur in response to an oral load of Na and to
infusion of synthetic atrial natriuretic factor (ANF) were examined in
conscious dogs with an arteriovenous (AV) fistula and chronic compensated
high-output heart failure. After ingestion of a meal containing 125 meq Na,
plasma iANF and right atrial pressure increased from high basal levels of
506 +/- 46 pg/ml and 96 +/- 5 mmH2O to peak responses of 728 +/- 43 pg/ml
(P less than 0.05) and 104 +/- 6 mmH2O (P less than 0.05). These increases
were associated with a brisk postprandial natriuresis and diuresis of a
magnitude previously observed in normal dogs. Synthetic ANF infusions that
achieved plasma iANF levels of similar and higher magnitude to those
observed during the feeding experiments did not produce a significant
natriuresis in these AV fistula dogs. In separate series of experiments,
chronic effects of normal and low-Na diets on daily Na excretion and
postabsorptive plasma iANF, renin, and aldosterone were studied in normal
and AV fistula dogs. During the normal Na diet of 40 meq/day, both groups
had normal levels of renin and aldosterone, but Na balance was achieved in
AV fistula animals in the presence of a fourfold elevation in plasma iANF
compared with normal dogs (P less than 0.05). During 2 wk of Na
restriction, cumulative negative Na balance and marked stimulation of renin
and aldosterone were similar in normal and AV fistula animals, but plasma
iANF did not change significantly in either group.(ABSTRACT TRUNCATED AT
250 WORDS)
