Table 2.
Rank order of binding affinities of natural and synthetic steroids to CHO and MCF-7 cells transfected with human nPR
| Compounds | pIC50 (mean) | logRBA |
|---|---|---|
| Promegestone | 8.90 | 2.18 |
| 16α-ethyl-21-hydoxy-19-norpregn-4-ene-3,20-dione (Org 2058) | 8.72 | 2.00 |
| 19-Norprogesterone | 8.53 | 1.81 |
| Mifepristone | 8.26 | 1.54 |
| 17-Hydroxy-19-nor-17α-pregn-4-en-3-one | 8.24 | 1.52 |
| Progesterone | 7.87 | 1.15 |
| Desogestrel | 7.80 | 1.08 |
| 17β-Hydroxy-16α-isopropylestr-4-en-3-one | 7.72 | 1.00 |
| 17β-Hydroxy-17α-methylestr-4-en-3-one | 7.66 | 0.94 |
| Ethylestrenol | 7.21 | 0.49 |
| Nandrolone | 7.20 | 0.48 |
| Allylestrenol | 7.04 | 0.32 |
| Ethisterone | 6.99 | 0.27 |
| Lynestrenol | 6.95 | 0.23 |
| 5α-Dihydronandrolone | 6.50 | −0.22 |
| 5α-Dihydrotestosterone (DHT) | 6.16 | −0.56 |
| Androst-4-ene-3,17-dione (androstenedione) | 6.02 | −0.70 |
| Testosterone | 6.02 | −0.70 |
Each value is the mean of at least three separate competitive binding assays. IC50 is the competitor concentration (nM) that causes 50% displacement of [3H] Org 2058. RBA (Relative Binding Affinity), RBA (%) compared with that of Org 2058.