The role of peptides from the N-terminus and C-terminus of the 126 amino acid (a.a.) atrial natriuretic factors (ANF) prohormone in modulating renal sodium and water handling in cirrhotic patients has not been defined. Eight cirrhotic individuals were evaluated; their mean basal circulating concentration of the C-terminus (a.a. 99-126; i.e., ANF) was 25 ± 2 fmol/ml, not different from the 22 ± 1 fmol/ml value found in 54 normal volunteers. On the other hand, the basal circulating concentrations of the whole N-terminus (a.a. 1-98) and the midportion of the N-terminus (namely a.a. 31-67; pro ANF 3l -67) of the ANF prohormone in these cirrhotic subjects of 704 ± 52 and 654 ± 83 fmol/ml were significantly elevated (p < 0.05; ANOVA) in comparison to control values (531 ± 25, 317 ± 22 fmol/nkm resoectuvekt). Following equilibration on a 10 mmol/day sodium diet, the responsiveness of the N-terminus and C-terminus of ANF prohormone to 3h of water immersion, which induces marked acute central volume expansion, was evaluated in these 8 seated cirrhotic patients. There was a prompt increase in the circulating concentrations of immunoreactive (ir) pro ANF 1-98 (whole N-terminus), ir pro ANF 3l -67, and ir ANF (C-terminus) within 15 min of immersion (p < 0.05; ANOVA) compared to their preimmersion values. The response of circulating ir pro ANF 1-98, pro ANF 3l-67, and ANF concentrations in these 8 cirrhotic subjects to immersion was significantly greater (p < 0.05; ANOVA) than that of 7 healthy volunteers undergoing an identical 3-hour immersion study. With cessation of immersion, the C-terminus decreased within 30 min to a concentration not significantly different from preimmersion values, whereas the N-terminus and pro ANF 3l-67 remained significantly elevated after 1 h.
- Central hypervolemia
- Prohormone atrial natriuretic peptides
ASJC Scopus subject areas