Evidence for endothelin-1 release from resistance vessels of rats in response to hypoxia

To elucidate further the contribution of endothelin into endothelium-dependent vasoconstriction evoked by hypoxia, we observed endothelin release during hypoxia. Endothelin was detectable in perfusate from mesenteric artery. Immunoreactive endothelin was confirmed as endothelin-1 by a reverse phase-HPLC. Endothelin release increased 4.1 +/- 1.3 to 12.4 +/- 2.0 pg/30 min without changing perfusion pressure. Thirty minutes of hypoxia stimulated endothelin release by 71 +/- 11% (P less than 0.05) and was associated with an elevation of perfusion pressure. These results suggest that endothelin contributes to endothelium-dependent vasoconstriction by hypoxia in mesenteric artery and may play an important role in the local peripheral vascular tone.