Natriuretic peptides stimulate cyclic guanosine monophosphate production in human saphenous vein and internal mammary artery

Objective: It has been shown previously that the internal mammary artery re leases more cyclic guanosine monophosphate after stimulation with atrial na triuretic peptide than the saphenous vein, and that C-type natriuretic pept ide possesses a cyclic guanosine monophosphate stimulating potential on sap henous vein bypass grafts. The present study was undertaken to investigate intracellular content and extracellular release of cyclic guanosine monopho sphate, by the internal mammary artery and saphenous vein, after challenge with further members of the natriuretic peptide family. Methods: Specimens of human internal mammary artery and saphenous vein from 29 patients were c ut into segments and stimulated with 10(-6) M concentrations of atrial natr iuretic peptide (internal mammary artery n = 8, saphenous vein n = 10), bra in natriuretic peptide (internal mammary artery n = 9, saphenous vein n = 1 3), C-type natriuretic peptide (internal mammary artery n = 12, saphenous v ein n = 15), and urodilatin (internal mammary artery n = 8, saphenous vein n = 12). Intracellular content and extracellular release of cyclic guanosin e monophosphate were determined using an I-125 radioimmunoassay. Results: T he following median stimulated intracellular cyclic guanosine monophosphate concentrations were measured in the internal mammary artery and saphenous vein: 35358 and 8672 fmol/cm(2) (P < 0.003) after atrial natriuretic peptid e, 45632 and 7830 fmol/cm(2) (P = 0.003) after brain natriuretic peptide, 1 0144 and 13216 fmol/cm(2) (P = NS for intergraft comparison) after C-type n atriuretic peptide, and 20949 and 6690 fmol/cm(2) (P = 0.001) after urodila tin. Stimulation with atrial natriuretic peptide, brain natriuretic peptide and urodilation also led to a significant increase of extracellular cyclic guanosine monophosphate release by the internal mammary artery. Conclusion : We conclude that brain natriuretic peptide and urodilatin exhibit a simil arly effective cyclic guanosine monophosphate-stimulating potential on the internal mammary artery as atrial natriuretic peptide. In contrast, C-type natriuretic peptide shows comparable effects on the internal mammary artery and saphenous vein. (C) 2000 Elsevier Science B.V. All rights reserved.