Presence of immunoreactive endothelin-1 and atrial natriuretic peptide in human pericardial fluid

This study was undertaken to characterize endothelin-1 (ET-1) and atrial natriuretic peptide (ANP) concentrations in human pericardial fluid, blood plasma, right atrial appendage and papillary muscle by use of specific radioimmunoassays. In patients undergoing cardiac surgery (n=16) pericardial fluid mean immunoreactive (ir-) ET-I and ir-ANP levels were 36-fold and 4-fold higher than corresponding plasma levels, respectively. In high performance liquid chromatography (HPLC) pericardial fluid ir-ET-1 was indistinguishable from human ET-1[1-21] and the majority of pericardial fluid ir-ANP coeluted with human ANP[99-126]. Atrial tissue ir-ET-l and ir-ANP concentrations were 17-fold and 870-fold higher than in ventricular tissue. Our present study demonstrated for the first time the presence of ir-ET-l in the pericardial fluid in humans. Human pericardial fluid contained far the highest concentrations of ET-1 among all biological fluids tested thus far. The functions of pericardial fluid ET-I and ANP on cardiac performance and coronary vascular tone require further investigations.