RADIOLIGAND BINDING-STUDIES REVEAL MARKED SPECIES-DIFFERENCES IN THE VASOPRESSIN-V(1) RECEPTOR OF RAT, RHESUS AND HUMAN TISSUES

The [H-3]arginine-vasopressin ([H-3]AVP) binding site in rat, rhesus and human liver and nonpregnant human uterus was characterized and contrasted. [H-3]AVP bound with high affinity (K(i) values, 0.2-0.6 nM) to preparations of all tissues studied. Competition binding studies using a series of compounds from three structural classes indicate a marked species difference between the rat and primate liver AVP-V1 site. This site in rhesus and human liver however, is essentially identical, indicating that the rhesus liver is an appropriate surrogate for human tissue. These studies also indicate that the AVP-V1 site of nonpregnant human uterus and human liver is equivalent.