Molecular forms of brain and atrial natriuretic peptides in transplanted human heart

We examined the molecular forms of brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) in endomyocardial right ventricular extracts from cardiac transplant recipients, using gel chromatographic separation coupled with specific radioimmunoassay techniques. Two distinct molecular forms of ANP and BNP were observed in the ventricular extracts consistent with the biologically active alpha-human peptides and the gamma-precursor peptides. Alpha-BNP was predominant and constituted 75 +/- 3% (n = 5) of the total immunoreactive BNP, while 21 +/- 2% (n = 5) of the total immunoreactivity comprised gamma-BNP. In contrast, gamma-ANP constituted 89 +/- 4% (n = 5) of the total immunoreactive ANP and was dominant over alpha-ANP, which made up 10 +/- 2% (n = 5) of the total immunoreactivity. There was no evidence for altered processing of BNP and ANP precursors in the right ventricular tissues from the de-nervated transplanted human heart. These findings provide further insight by identifying the molecular forms of BNP and ANP present in the transplanted human heart.