Table 2.

Dissociation constants (K_d) of PGE₂ for EP receptor subtypes in various species

Receptor	Kd (nM) (human)	Kd (nM) (rat)	Kd (nM) (mouse)
EP1	25 (Abramovitz et al., 2000)	24 (Boie et al., 1997)	21 (Watabe et al., 1993)
	16 (Sharif and Davis 2002)
EP2	13 (Abramovitz et al., 2000)	5 (Boie et al., 1997)	116 (Nishigaki et al., 1996)
	12.9 (Stillman et al., 1998)
EP3	0.33 (Abramovitz et al., 2000)	1 (Boie et al., 1997)	2.9 (Sugimoto et al., 1992)
EP4	0.59 (Abramovitz et al., 2000)	1 (Boie et al., 1997)	1.27 (Nishigaki et al., 1996)
	0.72 (Davis and Sharif, 2000)
	1.12 (Marshall et al., 1997)

Abbreviations: EP, E prostanoid; PGE₂, prostaglandin E₂.