Plasma Concentration of α-Hanp and Renal Responses to α-Hanp Infusion in Patients with Congestive Heart Failure and Those with Chronic Renal Failure

Abstract

To study the role of α-human atrial natriuretic polypeptide (α-hANP) in body fluid regulation, we measured the plasma concentration of α-hANP and renal function in 9 patients with congestive heart failure (CHF), 10 with chronic renal failure (CRF) and 8 normotensives (NT) before and during α-hANP infusion at 0.025 μg/kg·min. The plasma concentration of α-hANP was significantly higher in the CHFs and CRFs than in the NTs (319, 168 and 72 pg/ml, respectively). Alpha-hANP infusion decreased mean blood pressure in a similar manner in the 3 groups (-5%, p < 0.01 each). Increases in urinary sodium excretion and glomerular filtration rate during α-hANP infusion, however, were greater in the CHFs and CRFs than in the NTs. Furthermore, the higher the preinfusion level of renal vascular resistance (RVR), the greater was the reduction in RVR by α-hANP (r=-0.80, p < 0.001). The metabolic clearance rate (MCR) of α-hANP was significantly smaller in the CHFs and CRFs than in the NTs (38, 35 and 67 ml/min·kg, respectively). These results suggest that the renal vasodilatory actions of α-hANP seem to be enhanced in patients with increased RVR and that the elevation of the basal plasma concentration of α-hANP in CHFs and CRFs may be in part due to the low MCR. © 1988, The Japanese Circulation Society. All rights reserved.