Effect of diabetes and bosentan treatment on VSM and endothelial cell ET receptors. Endothelium-intact (vETA, vETB, and eETB) and endothelium-denuded (vETA and vETB) MCAs were used in immunoblotting experiments, and eETB was calculated as the difference in band intensities of intact and denuded vessels. A, representative immunoblots are shown. B and C, ETA (B) and vETB (C) receptor density measured on endothelium-denuded vessels was increased in diabetes and was restored to control levels by bosentan treatment. D, there was no disease or treatment effect on eETB protein levels. Results are given as mean ± S.E.M. *, p < 0.001 versus control. **, p < 0.001 versus vehicle.