ALTERATION OF PLASMA ENDOTHELIN-1 BY EXERCISE AT INTENSITIES LOWER AND HIGHER THAN VENTILATORY THRESHOLD

The purpose of this study was to investigate whether the release of endothelin-1 (ET-1), a potent vasoconstrictor peptide produced by vascular endothelial cells, is induced by exercise. Venous plasma concentrations of ET-1 were measured by sandwich-enzyme immunoassay before and after endurance exercise with a cycle ergometer at different intensities. Male intercollegiate athletes participated in the study and performed cycle ergometer exercise of 30 min duration at intensities of 90 or 130% of their individual ventilatory threshold (VT). The plasma concentration of ET-1 was slightly but significantly increased after exercise at 90% and markedly increased after exercise at 130% of individual VT. The increase in ET-1 was greatest 30 min after exercise at both intensities. It was first demonstrated that the plasma concentration of ET-1 was significantly increased after exercise: the greater the intensity, the greater the extent of the increase in plasma ET-1 concentration. However, the precise physiological roles of ET-1 during exercise remain to be elucidated.