Blunted natriuretic response and low blood pressure after atrial natriuretic factor in early cirrhosis

We compared the natriuretic response to a standard dose of atrial natriuretic factor in nine patients with early cirrhosis (no ascites or edema) with the response in normal subjects displaying a range of baseline sodium excretions due to different sodium intakes (20 mmoles per day, n = 9; 100 mmoles per day, n = 9, and 200 mmoles per day, n = 9). In these normal subjects, sodium output rose, in the same order, from 49 +/- 12 to 177 +/- 26, from 116 +/- 21 to 365 +/- 106 and from 228 +/- 29 to 901 +/- 85 mumoles per min in the first 20 min after 100 micrograms atrial natriuretic factor (human atrial natriuretic factor 99-126). Thus, irrespective of basal excretion, natriuresis rose by at least 2-fold. In the cirrhotic patients, natriuresis rose from 173 +/- 42 to 305 +/- 77 mumoles per min, that is by hardly 1-fold, significantly less than in the normal subjects (p less than 0.01). Renal function studies indicated that atrial natriuretic factor caused less rise in glomerular filtration rate and in fractional sodium excretion. Atrial natriuretic factor induced a fall in blood pressure only in the cirrhotic group, from 130 +/- 4/81 +/- 2 to 108 +/- 4/68 +/- 3 mmHg (p less than 0.001). Plasma atrial natriuretic factor was not low in the cirrhotic patients. Although these data are compatible with a primary disturbance of sodium excretion in early cirrhosis without ascites, such an explanation is complicated by the concomitant drop in blood pressure after atrial natriuretic factor.(ABSTRACT TRUNCATED AT 250 WORDS)