BOTH PLASMA AND RENAL ENDOTHELIN-1 PARTICIPATE IN THE ACUTE CARDIOVASCULAR-RESPONSE TO EXERCISE

Plasma endothelin (ET-1) and renal endothelin are two distinct functio nal systems involved in maintaining blood volume. To investigate wheth er plasma and renal ET-1 participate in the cardiovascular response to exercise-induced hypovolaemia, we studied changes in plasma and urina ry ET-1 in healthy non-professional athletes after 2h of jogging perfo rmed both without and with drinking isotonic fluids. After the run, wh ich caused a 13% plasma volume (PV) reduction, plasma and renal ET-1 ( +117% and +118%) increased significantly (all P<0.01). Fluid loss rest itution during the run significantly attenuated either the PV contract ion (-1.2%) and plasma and renal ET-1 increase (+2 and +3%). At multip le regression analysis changes in AVP plasma concentration, and not in PRA or PV per se, were significantly related to ET-1 changes both in plasma and urine. The present findings indicate that both plasma and r enal ET-1 participate in the cardiovascular response to hypovolaemia i nduced by long-lasting, dynamic exercise.