Autoradiographic localization of binding sites for epidermal growth factor-urogastrone (EGF-URO) in coronary arteries

Previously published data have indicated that epidermal growth factor-urogastrone (EGF-URO) can regulate blood flow in vivo and can modulate vascular smooth muscle contractility in vitro. However, the exact location of the receptors responsible for this vascular action of EGF-URO has not been previously determined. In this report, employing in vitro autoradiography with 125I-labeled EGF-URO, we have documented the presence of specific EGF-URO binding sites in the tunica media of bovine and porcine coronary arteries. Our observations support the indirect evidence pointing to presence of EGF-URO receptors on the smooth muscle elements of arterial tissue. Our data also support further the hypothesis that EGF-URO and related growth factors (like TGF-alpha or PDGF) may play a role in normal and pathophysiological vascular function.