EDNRA and chronic kidney disease: Although the mRNA levels of the ETA and ETB receptors, prepro-ET-1 and endothelin converting enzyme were unaltered in bulk lung tissue (Table 3), immunohistochemical staining for the ETB receptor in a subset of animals showed a reduced ETB expression in the pulmonary endothelial cells of DM + HC + CKD swine (Fig. 2).