Circulating beta-atrial natriuretic factor in congestive heart failure in humans.
BACKGROUND
beta-Atrial natriuretic factor (beta-ANF) is an antiparallel dimer of alpha-ANF (alpha-ANF) with diminished cyclic GMP generation in vitro. To date, the presence of beta-ANF in the circulation of humans with severe congestive heart failure (CHF) remains controversial. The current study was designed to determine the presence and magnitude of circulating beta-ANF in severe CHF, to correlate plasma beta-ANF with the degree of ventricular dysfunction, and to investigate the role of human plasma and atrial tissue in the degradation of beta-ANF.


RESULTS
Venous plasma samples were obtained from patients (n = 12) with severe CHF and normal volunteers (n = 8). Total plasma ANF was measured by radioimmunoassay. alpha-ANF and beta-ANF in nonextracted plasma were separated by gel filtration chromatography using a P-6 column. Right atrial tissue samples (n = 5) were collected from a different group of patients at the time of open-heart surgery. 125I beta-ANF and I125 ANF were incubated with atrial tissue or plasma. The corresponding peak areas of beta-ANF were determined by Tamaya Digital Planimeter. beta-ANF represented 61% of total plasma ANF in CHF patients and was not detected in normal human plasma. The elevation of beta-ANF correlated with the severity of ventricular dysfunction. Thirty percent of beta-ANF and 100% alpha-ANF were converted to smaller peptide fragments in atrial tissue no conversion in plasma.


CONCLUSIONS
beta-ANF is the principal form of circulating ANF in patients with severe CHF and correlates with the degree of left ventricular dysfunction. beta-ANF is not generated from alpha-ANF and may be degraded rapidly in atrial tissue to smaller peptide fragments that do not occur in plasma. As beta-ANF is reported to have reduced biological action, the current studies may support the conclusion that the ANF system in CHF has reduced functional activity despite increases in circulation concentrations.
Wei
C M
CM
Cardiorenal Research Laboratory, Mayo Clinic, Rochester, MN 55905.
Kao
P C
PC
Lin
J T
JT
Heublein
D M
DM
Schaff
H V
HV
Burnett
J C
JC
D000368:Aged; D009320:Atrial Natriuretic Factor / Q000097:blood* / Q000737:chemistry; D002850:Chromatography, Gel; D005260:Female; D006325:Heart Atria / Q000378:metabolism; D006333:Heart Failure / Q000097:blood* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay; D016277:Ventricular Function, Left / Q000502:physiology
D009320:Atrial Natriuretic Factor