“…Indeed, PR activation studies show that a double bond added into the A-ring of 11β-hydroxydihydroprogesterone (11βOHDHP4) significantly increases activity. 40 Additionally, we have not accounted for full versus partial agonistic activity of the ligands here, as we have focused solely on EC 50 values. Further work will be required to determine whether there is an evolutionary basis for partial agonistic activity reported for steroidal PR ligands.…”