TABLE 6.
Dissociation constants for steroidal antagonists of activator-induced calcium influx in human sperm
| Opener | Antagonist | Schild | Leff-Dougall |
|---|---|---|---|
| pKB | |||
| PROG | MPA | 6.19 ± 1.75 | 6.16 ± 0.39 |
| LNG | 6.80 ± 0.10 | 5.47 ± 0.23 | |
| ALDO | 5.38 ± 0.27 | 5.46 ± 0.16 | |
| PGE1 | MPA | 5.38 ± 0.59 | 6.00 ± 0.26 |
| LNG | 3.36 ± 0.41 | 5.50 ± 0.11 | |
| ALDO | 3.14 ± 0.95 | 5.22 ± 0.20 | |
| l-Sirenin | MPA | 5.22 ± 0.33 | 5.20 ± 0.20 |
| LNG | 4.25 ± 0.23 | 5.07 ± 0.05 | |
| ALDO | 4.82 ± 1.03 | 5.19 ± 0.16 | |
The Schild pKB values (mean ± standard error) were obtained using the EC50 values corresponding to the pEC50 values listed in Table 5 derived from 3–8 independent experiments. For all Schild analyses, the slopes of the regression lines had values of 1.0 within the 95% CI. The Leff-Dougall pKB values (mean ± SD) were obtained using the IC50 values corresponding to the pIC50 values listed in Table 4 derived from 5–12 independent experiments.