Plasma levels of human atrial natriuretic peptide in uremic patients on dialysis treatment

Plasma levels of human atrial natriuretic peptide (hANP) were measured in 19 uremic patients on chronic hemodialysis and 9 patients on CAPD. Measurement of hANP was performed by radioimmunoassay with extraction procedure. A preliminary study by gel chromatography revealed some immunoreactive peaks other than hANP (1-28), which were thought to be smaller fmagments of hANP (1-28). Plasma levels of hANP in hemodialysis patients were significantly higher than those of CAPD patients and those of normal controls (271.8±173.4pg/ml, 81.8±80.5pg/ml, and 31.5±19.8pg/ml, respectively). After 4 hours of hemodialysis treatment, plasma hANP levels decreased to 100.4±50.1pg/ml, The change in hANP during hemodialysis was positively correlated with those in serum creatinine and body weight. Clearance of hANP by hemodialysis was higher than expected from its molecular weight. Plasma hANP levels decreased during ECUM. The lower plasma hANP levels seen in CAPD patients were possibly attributable to the better control of ECF volume and larger clearance of hANP by CAPD. These data suggest that plasma levels of hANP in chronic dialysis patients depend on such factors as accumulation of fragments of hANP, ECF volume status, and clearance of hANP by hemodiaysis and CAPD.