2 AROMATIC RESIDUES REGULATE THE RESPONSE OF THE HUMAN OXYTOCIN RECEPTOR TO THE PARTIAL AGONIST ARGININE-VASOPRESSIN

We investigated the mechanisms that regulate the efficacy of agonists in the arginine-vasopressin (AVP)/oxytocin (OT) receptor system, In th is paper, we present evidence that AVP, a full agonist of the vasopres sin receptors, acts as a partial agonist on the oxytocin receptor, We also found that AVP becomes a full agonist when two aromatic residues of the oxytocin receptor are replaced by the residues present at equiv alent positions in the vasopressin receptor subtypes, Our results indi cate that these two residues modulate the response of the oxytocin rec eptor to the partial agonist AVP.