Table 2.

Synopsis of agonist (induction of vasoconstriction response) and/or antagonist (inhibition of hU-II-mediated vasoconstriction) properties of hU-II, urantide, GSK248451 and SB-710411 in rat, cat and monkey isolated arteries

Vessel	hU-II	GSK248451	Urantide	SB-710411
Rat aorta	Agonist (full)	Antagonist	Antagonist	Antagonist
Cat femoral artery	Agonist (full)	Antagonist	Agonist (weak partial)	Antagonist
Cat aorta	Agonist (full)	Antagonist	Agonist (weak partial)	Inactive
Monkey renal artery	Agonist (full)	Antagonist	Agonist (moderate partial)	Agonist (moderate partial)
Monkey mesenteric artery	Agonist (full)	Antagonist	Agonist (moderate partial)	Agonist (full)

Weak partial agonists were defined as those exhibiting a relative efficacy [α] <0.5. Moderate partial agonists exhibited relative efficacies [α]⩾0.5 to ⩽0.9. Full agonists possessed relative efficacies [α] >0.9 (intrinsic activities are expressed relative to hU-II, considered a full agonist where relative efficacy [α] is 1.0). ‘Inactive' entities (10 μM) exhibited neither agonist nor antagonist properties in the vessels studied (see Tables 3 and 4).