A POSSIBLE CONTRIBUTION OF ENDOGENOUS ATRIAL-NATRIURETIC-PEPTIDE TO PROTEINURIA IN PATIENTS WITH CHRONIC-RENAL-FAILURE

Plasma levels of immunoreactive atrial natriuretic peptide (IR-ANP) we re measured with a specific radioimmunoassay in 19 undialysed patients with chronic renal failure. At the beginning, an extremely high level of plasma hANP (50 fmol/ml) seen in a patient was rejected with Smirn ov's test and was excluded from further statistics. The plasma IR-ANP levels in these patients were significantly higher than those of 19 no rmal subjects matched with age and sex (10.9 +/- 1.6 vs 5.3 +/- 0.6 fm ol/ml, mean +/- SEM, p < 0.01), and positively correlated with mean bl ood pressure (r = 0.44, p < 0.05) and the cardiothoracic ratio (r = 0. 65, p < 0.01), but did not correlate with creatinine clearance (r = -0 .38, n.s.). Further, a significant correlation was observed between pl asma IR-ANP and urinary protein output (r = 0.47, p < 0.05). On the ot her hand, urinary protein output did not correlate significantly with variables such as mean blood pressure, the cardiothoracic ratio or cle arance. Since it has been suggested that ANP enhances glomerular capil lary permeability, increased ANP responding to volume overload in thos e patients may play an important role in increasing urinary protein ex cretion.