Determination of plasma concentrations of endothelin-1(1-31) and endothelin-1 in healthy subjects and patients with atherosclerosis.

We previously found that human chymase cleaves big endothelins at the Tyr31-Gly32 bond and produces 31-amino-acid endothelins, endothelins(1-31). Endothelin-1(1-31) has been isolated from a number of human organs, including the heart and lungs. As endothelin-1 has been shown to play a significant role in the paracrine regulation of cardiovascular functions in humans, it is possible that endothelin-1(1-31) may also exhibit biological activity on human tissues. We previously reported that synthetic endothelin-1(1-31) exhibits a number of physiological actions on cultured cells in vitro. In the present study, we investigated the plasma concentrations of endothelin-1(1-31) and endothelin-1 in healthy subjects and compared them with those in patients with cardiovascular diseases. Endothelin-1(1-31) and endothelin-1 in human plasma was measured using a sandwich-enzyme-immunoassay system, which was recently described for measurement of endothelin-1(1-31). The plasma concentrations of endothelin-1(1-31) and endothelin-1 in healthy volunteers were 19.24 +/- 5.70 and 15.54 +/- 4.45 pg/ml (n = 5), respectively. We also measured plasma concentrations of endothelin-1(1-31) and endothelin-1 before and after surgery in patients with abdominal aortic aneurysms. Before surgery, plasma concentrations of endothelin-1(1-31) and endothelin-1 in these patients were higher than those in healthy individuals. After surgery, both endothelin-1(1-31) and endothelin-1 in plasma decreased to levels similar to those of healthy subjects. This suggests that endothelin-1(1-31) may have similar physiological significance to endothelin-1 in patients with atherosclerosis.