Inhibitory Effect of Atrial Natriuretic Peptide on Accelerated Endothelin Secretion from Cultured Human Endothelial Cells

This study investigated the effect of atrial natriuretic peptide (ANP) on endothelin (ET) secretion from cultured human endothelial cells. Confluent umbilical venous endothelial cells were incubated with experimental agents in multi-well plates, and the level of immunoreactive ET in the medium was measured by radioimmunoassay. There was no significant effect of ANP (10(-8), 10(-7) and 10(-6) M) on ET secretion after a 3- or 6-hour incubation. However, with 24-hour incubation, ANP significantly inhibited ET secretion from cultured human endothelial cells (control, 139.0 +/- 7.2 fmol/well; 10(-7) M, 89.4 +/- 4.7 fmol/well; 10(-7) M, 79.4 +/- 8.2 fmol/well; 10(-6) M, 71.0 +/- 10.1 fmol/well, P < 0.01). Furthermore, the addition of 8-bromo-cyclic GMP to the medium inhibited ET secretion (control, 147.2 +/- 2.9 fmol/well; 10(-5) M, 140.9 +/- 2.3 fmol/well; 10(-4) M, 143.0 +/- 1.0 fmol/well; 10(-3) M, 96.6 +/- 6.3 fmol/well, P < 0.01). These findings demonstrate that ANP inhibits accelerated ET secretion from cultured human endothelial cells, probably due to augmentation of intracellular cyclic GMP levels by ANP-activated guanylate cyclase.