The atrial natriuretic factor hormonal system in the regulation of sodium excretion in dogs with experimental heart failure.

In response to a meat meal containing 125 mEq of sodium, conscious dogs (n = 5) with an arteriovenous (AV) fistula and chronic compensated heart failure exhibited temporally related increases in postprandial plasma immunoreactive atrial natriuretic factor (iANF), right atrial pressure, and sodium excretion. In separate experiments, two weeks of dietary sodium restriction produced similar marked stimulation of renin and aldosterone both in normal dogs (n = 5), and in AV fistula dogs (n = 5) with chronic high circulating levels of ANF. Plasma iANF did not change (P greater than .05) in either group. These results suggest that the ANF system is involved in the postprandial regulation of sodium excretion in the AV fistula dogs with compensated heart failure. In the postabsorptive state, however, the activity of the renin-aldosterone axis is closely related to dietary sodium intake and appears to function independently of the ANF system for the prevention of sodium loss.