TABLE 5

Some of the key radiolabeled ligands at the apelin receptor and their binding affinities

Ligand	Action	Binding Affinity	Units	References
[¹²⁵I][Nle⁷⁵,Tyr⁷⁷]apelin-36 (human)	Full Agonist	11.2	pK_d	Kawamata et al., 2001
[¹²⁵I][Glp⁶⁵, Nle⁷⁵, Tyr⁷⁷]apelin-13	Full Agonist	10.7	pK_d	Hosoya et al., 2000
[¹²⁵I][Pyr¹]apelin-13	Full Agonist	9.5	pK_d	Katugampola et al., 2001
[³H][Pyr¹][Met(0)11]-apelin-13	Full Agonist	8.6	pK_d	Medhurst et al., 2003
[¹²⁵I]apelin-13	Full Agonist	9.2	pK_d	Fan et al., 2003