Fig 2. Binding of DHT, T, 11KDHT and 11KT to the human AR (A) and transactivation via an ARE (B and C).

Binding affinities, agonist potencies and efficacies of DHT, 11KDHT, T and 11KT relative to the synthetic AR agonist mibolerone are summarised in (D). Whole cell binding assays (A) were conducted in COS-1 cells transiently transfected with pSVARo. Cells were incubated with 0.2 nM [³H]-Mib in the absence and presence of increasing concentrations of either unlabelled Mib, DHT, 11KDHT, T and 11KT for 16 hours. Results are plotted as % specific binding where the total specific binding of [³H]-Mib only is set to 100% and binding of unlabelled steroid is set as a % binding relative to that. Whole cell binding results are shown as means ± SEM of three independent experiments performed in triplicate. Transactivation assays (B and C) where performed in COS-1 cells transiently transfected with the pSVARo expression vector and the 4xSC ARE1.2-luc reporter. Agonist activity was measured by incubating cells in the presence of increasing concentrations of either Mib, DHT, T, 11KDHT or 11KT for 24 h. Induction is shown as % luciferase activity expressed in relative light units (rlu’s), with the maximal response of Mib (10⁻⁵ M) set to 100%. Luciferase assays are shown as means ± SEM of six independent experiments performed in quadruplicate.