... kidneys showed high, single-affinity specific binding to ETA and ETB receptors, with a &,of 0.17fO.O4nmol/l [l2]. Using the subtype-selective ligands BQ 123 (an ETA antagonist) and BQ3020 (an ETB agonist, Fig. 1) in autoradiographic and binding studies it became evident that, unlike other tissues, human...