AJP - Regulatory, Integrative and Comparative Physiology, Vol 252, Issue 5 921-R924, Copyright © 1987 by American Physiological Society
Role of atrial natriuretic factor in the natriuresis of acute volume expansion
A. A. Khraibi, J. P. Granger, J. C. Burnett Jr, K. R. Walker and F. G. Knox
The quantitative role of atrial natriuretic factor (ANF) in mediating the
natriuresis induced by acute volume loading was determined in these
studies. Plasma level of ANF (PANF), glomerular filtration rate (GFR), and
renal excretory responses were measured in three groups of anesthetized
Sprague-Dawley rats. In one group of rats (n = 8), acute volume expansion
was established by intravenous infusion of saline (5% body wt) over a
period of 30 min. A second group of rats (n = 13) was infused with
synthetic ANF (2 micrograms X kg-1 X h-1 iv) to mimic the high PANF
observed during acute volume loading. A third group (n = 13) served as
control. PANF was similar and significantly elevated (P less than 0.05) in
volume-expanded and ANF-infused groups compared with control. In control
rats, PANF measured 122.0 +/- 12.1 pg/ml, whereas it averaged 389.4 +/-
30.3 pg/ml for volume-expanded and 368.1 +/- 22.3 pg/ml for ANF-infused
rats. GFR was also comparable and significantly increased (P less than
0.05) in volume-expanded and ANF-infused groups compared with control rats.
Infusion of ANF at a dose to mimic PANF obtained during acute volume
expansion resulted in a fourfold increase in the fractional excretion of
sodium. The results of these studies suggest that ANF may play an important
quantitative role in promoting natriuresis during acute volume expansion.
