Table 5.
Signaling efficiency (EC50) of eicosanoids on the recombinant EP receptors expressed in cell cultures and in human duodenum cells
| EC50 (nM) | ||||||
|---|---|---|---|---|---|---|
| Receptor/cell line | PGE1 | PGE2 | PGF2α | PGD2 | PGI2 analog | Reference |
| hEP1/CHO | - | 1.98 | - | - | Sekido et al. 2016 | |
| hEP1/HEK293 | 9.3 | 2.90 | 29 | 3,200 | 319 | Ungrin et al. 2001 |
| hEP2/CHO | - | 3.74 | - | - | - | Sekido et al. 2016 |
| mEP2/CHO | - | 1.0 | - | - | - | Nishigaki et al. 1995 |
| hEP2/COS7c | - | 50 | - | - | - | Regan et al. 1994a |
| hEP2/hNPE | - | 4.9 | 964 | 2973 | - | Sharif et al. 2003 |
| hEP3/CHO | - | 1.60 | - | - | - | Sekido et al. 2016 |
| EP3/gp | - | 5.4 | - | - | - | Savage et al. 1993 |
| hEP4/CHO | - | 4.09 | - | - | - | Sekido et al. 2016 |
| hEP4/hNPE | - | 46 | >10,000 | >10,000 | >10,000 | Crider et al. 2000 |
| hEP4/human duodenum | - | 50 | - | - | - | Larsen et al. 2005 |
| mEP4/CHO | - | 1.0 | - | - | - | Nishigaki et al. 1995 |
Abbreviations: h, human; m, mouse; b, bovine; HEK293 human embryonic kidney cells; COS M-6, Green monkey kidney cells; COS7, monkey fibroblast-like cells; CHO. Chinese hamster ovary cells; COS-1, African green monkey kidney fibroblast-like cells; hNPE human non-pigmented ciliary epithelial cells; gp, guinea pig distal ileum tissue. The Ki values were determined from [3H]PGE2 displacement assays. The EC50 for recombinant EP1 and EP3 receptors were determined from intracellular changes in [Ca2+] and the EC50 for recombinant EP2 and EP4 receptors were determined from intracellular changes in cAMP. The EC50 values for hEP2 and hEP4 expressed in in hNPE cells were determined from intracellular changes in cAMP. The EC50 values determined for gEP3 gp (guinea pig vas deferens) tissue were determined by changes in the inhibition of twitch contraction values. The EC50 for hEP4 in human duodenum tissue was determined by changes in short circuit current. a) Ki values determined from reported IC50 and Kd utilizing the Cheng-Prusoff equation (Suganami et al. 2016); b) Values determined from IC50 estimated from binding curves and reported Kd utilizing the Cheng-Prusoff equations; c) Value estimated from a graph of [PGE2] vs. [cAMP].