Objective: To determine whether Dendroaspis natriuretic peptide (DNP), a novel peptide isolated from the venom of the Dendroaspis angusticeps snake that contains a 17-amino acid disulfide ring structure similar to that in atrial, brain, and C-type natriuretic peptides, is present in normal human plasma and myocardium and whether, like the other natriuretic peptides, DNP- like immunoreactivity (DNP-LI) is activated in human congestive heart failure (CHF). Material and Methods: Circulating DNP-LI was assessed in 19 normal human subjects and 19 patients with CHF (New York Heart Association class III or IV) with a specific and sensitive radioimmunoassay for DNP with no cross- reactivity with the other natriuretic peptides. Immunohistochemical studies that used polyclonal rabbit anti-DNP antiserum were performed on human atrial myocardial tissue obtained from four patients with endstage CHF who were undergoing cardiac transplantation and from three donor hearts at the time of transplantation. Results: We report that DNP-LI circulates in normal human plasma and is present in the normal atrial myocardium. In addition, DNP-LI is increased in the plasma of patients with CHF. Conclusion: This study demonstrates, for the first time, the presence of a DNP-like peptide in normal human plasma and in the atrial myocardium. Additionally, these studies demonstrate increased plasma DNP-LI in human CHF. These results support the possible existence of an additional new natriuretic peptide in humans, which may have a role in the neurohumoral activation that characterizes human CHF.
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