Levels of atrial natriuretic factor in the plasma and urine of patients with and without heart failure.

We assayed the concentrations of atrial natriuretic factor and guanosine 3',5'-phosphate in the plasma and urine of six healthy subjects, 12 patients with coronary artery disease and 11 patients with congestive heart failure. Patients with coronary artery disease had normal levels of atrial natriuretic factor in the plasma and urine and a normal excretion of guanosine 3',5'-phosphate, while those with congestive heart failure had a raised level of atrial natriuretic factor in the plasma, an increased excretion of 3',5'-guanosine phosphate and normal excretion of atrial natriuretic factor. Thus, measurement of atrial natriuretic factor in the urine can not replace the assay of the peptide in plasma.