Receptor binding affinities of some natural prostanoids at the major prostanoid receptors
| Compound | Receptor Binding Affinity (Ki) and Selectivity Parameters | ||||
|---|---|---|---|---|---|
| DP Receptors (human) | EP3 Receptors (bovine) | FP Receptors (bovine) | IP Receptors (human) | TP Receptors (human) | |
| nM | |||||
| PGD2 | 80 ± 5 | 1100 ± 150 (14×) | 2500 ± 760 (31×) | >148,000 (1850×) | >35,600 (445×) |
| PGE2 | 11,000 ± 2100 (3666×) | 3 ± 0.2 | 3358 ± 719 (1119×) | >40001-a (1333×) | N.D. |
| PGF2α | 18,000 ± 6400 (153×) | 24 ± 9 (−5×) | 118 ± 7 | >50,000 (424×) | >190,000 (1610×) |
| PGI2 | 35371-b (3×) | 5374 ± 1395 (4×) | 86,000 ± 29,000 (62×) | 1390 ± 724 | N.D. |
Values are mean ± S.E. for three to five experiments except for values for PGD2, which were from 63 experiments. Selectivity parameters (in parentheses) refer to the ratio of affinities between the nonpreferred receptor and the preferred receptor known for the particular prostanoid. Thus, for example, the preferred receptor for PGD2 is the DP receptor; for PGE2, it is the EP3 receptor; for PGF2α, it is the FP receptor; and for PGI2, it is the IP receptor. The Hill coefficients for the compounds competing at the DP receptor were 0.96 ± 0.03 for PGD2, 1.1 ± 0.04 for PGE2, and 0.94 ± 0.1 for PGF2α.