PlGF-mediated ET-1 expression involves PI-3 kinase, ROS, and HIF-1α. HPMVECs were treated with PlGF (250 ng/mL) for 6 hours, unless otherwise indicated, in the absence and presence of pharmacologic inhibitors or transfected with plasmids. (A-C) RNase protection assay. Data are representative of 3 different experiments. (D,E) ET-1 release by ELISA. Data are expressed as percentage change relative to untreated cells and represent means (± SE) of 3 independent experiments. ***P < .001; **P < .01; ns, P > .05. Where indicated, the vertical lines show the repositioned gel lanes.