Characterization of rodent liver and kidney AVP receptors: pharmacologic evidence for species differences

Abstract

Radioligand binding studies with [ 3H]vasopressin (AVP) were used to determine the affinities of AVP receptor agonists and antagonists for mouse liver and kidney plasma membrane preparations. Both membrane preparations exhibited one class of high-affinity binding site. AVP ligand binding inhibition studies confirmed that mouse liver binding sites belong to the V 1A subtype while kidney binding sites belong to the V 2 receptor subtype. The affinity of each ligand for mouse V 1A receptors was very similar to that for rat V 1A receptors, showing differences in K i values of less than 3-fold. In contrast, several peptide (d(CH 2) 5Tyr(Me)AVP) and nonpeptide (OPC-21268 and SR 49059) ligands had different affinities for mouse and rat kidney V 2 receptors, with differences in K i values ranging from 14- to 17-fold. These results indicate that mouse and rat kidney V 2 receptors show significant pharmacologic differences.