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	pKd	Kawamata et al., 2001
[125I][Glp65, Nle75, Tyr77]apelin-13	Full Agonist	10.7	pKd	Hosoya et al., 2000
[125I][Pyr1]apelin-13	Full Agonist	9.5	pKd	Katugampola et al., 2001
[3H][Pyr1][Met(0)11]-apelin-13	Full Agonist	8.6	pKd	Medhurst et al., 2003
[125I]apelin-13	Full Agonist	9.2	pKd	Fan et al., 2003