AJP - Endocrinology and Metabolism, Vol 258, Issue 1 E51-E56, Copyright © 1990 by American Physiological Society
Impaired aldosterone production by long-term infusion of atrial natriuretic factor
M. Nagano and E. L. Bravo
Department of Heart and Hypertension, Cleveland Clinic Foundation, Ohio 44195.
This study assessed the effect of chronic infusions of atrial natriuretic
factor (ANF) on in vivo and in vitro production of aldosterone. Vehicle
(saline) or rat ANF-(99-126) was intravenously infused at 100 ng.kg-1.h-1
for 5 consecutive days into male New Zealand White rabbits. At 5 days
plasma ANF was 18 +/- 4.1 pg/ml in vehicle-infused and 48.5 +/- 9.0 in
ANF-infused rabbits (P less than 0.01). Plasma renin activity was
significantly less in ANF-infused rabbits (2.99 +/- 0.35 vs. 0.77 +/- 0.12
ng.ml-1.h-1, P less than 0.01); however no differences were observed in the
basal plasma concentrations of aldosterone, corticosterone, potassium, or
hematocrit. In in vivo studies, chronically administered ANF attenuated
plasma aldosterone, but not pressor, responses to acutely infused
angiotensin II given at doses of 4, 16, and 64 ng.kg-1.min-1 for 20 min
each. In in vitro experiments, collagenase-dispersed adrenal capsular cells
from ANF-infused rabbits exhibited significantly reduced maximal responses
to adrenocorticotropic hormone, angiotensin II, and potassium. These
results suggest that chronic small increases in circulating ANF can blunt
selectively adrenocortical responses to aldosterone secretagogues without
affecting pressor responses to angiotensin II.
