AJP - Renal Physiology, Vol 258, Issue 6 1579-F1583, Copyright © 1990 by American Physiological Society
Role of atrial natriuretic factor in renal adaptation to variation of salt intake in humans
A. Dal Canton, G. Romano, G. Conte, L. De Nicola, A. Caglioti, P. Veniero, F. Uccello and V. E. Andreucci
Department of Nephrology, University of Catanzaro, Italy.
This study was performed to define the extent to which atrial natriuretic
factor (ANF) contributes to upregulate salt excretion in subjects eating a
high-salt diet. Eight normal volunteers were first studied at low-salt diet
(80 mmol NaCl/day); urinary sodium excretion (UNaV) and plasma ANF (PANF)
were measured in the basal condition and during stepwise infusion of human
alpha-ANF at 2, 4, 8, and 16 ng.min-1.kg-1. Then the same subjects were
shifted to a high-salt diet (400 mmol/day), and UNaV and PANF were measured
in the new balance condition. At low-salt diet, UNaV averaged 0.069
meq/min, and PANF averaged 21 pg/ml; infusion of human alpha-ANF raised
stepwise both UNaV and PANF (means in meq/min and pg/ml, respectively, were
0.177 and 46, 0.218 and 76, 0.360 and 86, and 0.601 and 182). Infusion of
ANF caused a progressive fall of plasma aldosterone and plasma renin
activity. Mean UNaV and PANF at high-salt diet were 0.301 meq/min and 35
pg/ml. Thus, by increasing experimentally PANF in a low-salt diet condition
to the levels occurring physiologically in a high-salt diet condition, a
significant rise in UNaV is evoked, which accounts for approximately 50% of
the rise of UNaV that is necessary to balance the increased salt intake.
