Table 2.
Transactivation EC50 values for dihydrotestosterone (DHT), estradiol (E2) and androstenediol (5-AED) for AR, ERα and ERβ.
| Ligand | Experimental System* | ||
|---|---|---|---|
| MDA-kb2(a) | T47D-kBluc(b) | ERβ-HEK293(c) | |
| DHT | 0.06 nM ± 0.01 (9) | 112 nM (1) | 409 nM ± 92 (6) |
| E2 | 851 nM ± 172 (6) | 0.001 nM ± 0.0003 (5) | 0.06 nM ± 0.02 (9) |
| 5-AED | 2969 nM ± 790 (7) | 2.5 nM ± 0.76 (4) | 1.7 nM ± 0.26 (7)** |
*Results are expressed as EC50 values in nM units, representing the statistical mean ± SEM. The numbers in parenthesis represent the number of independent experiments performed (n value).
(a)MDA-kb2 cells are stably transfected with a promoter/ reporter construct sensitive to sex steroid receptor stimulation fused upstream of (MMTV promoter) a luciferase reporter gene. These cells endogenously express both AR and glucocorticoid receptors.
(b)T47D-kBluc cells are stably transfected with a synthetic promoter/ reporter construct sensitive to estrogenic stimulation, consisting of 3 copies of the estrogen response element- (ERE-) fused upstream of a luciferase reporter gene. These cells express endogenously both ERα and ERβ.
(c)ERβ-HEK293 cells are transiently cotransfected with an ERE/luciferase promoter/reporter construct and a cDNA expression vector encoding the full length human ERβ. These cells exhibit virtually undetectable levels of endogenous sex steroid receptors.
**Although a total of 9 experiments were initially conducted, results from two experiments were discarded as clear outliers on the basis that their values fell >1.5 times the interquartile range above the third quartile of the entire dataset (standard statistical criterion for defining outlier values for a normally distributed population).