EDNRA and Hypertension: Incubation of human umbilical vein endothelial cells with EPO increased ET‐1 generation in a concentration‐dependent manner.32 In end‐stage renal disease patients, a significant increase in plasma ET‐1 levels was observed after a single dose of EPO.33 The potential role of ET‐1 in EPO‐induced hypertension is underlined by the fact that ETAR blockade prevented hypertension induced by EPO administration to uremic rats.29 In the present study, incubation of small arteries with EPO induced an increase in ET‐1 expression in the vascular wall.