Androstanedione

17β-DihydroAndrosterone (5α-androstane-3α,17β-diol; 3α-adiol), Androstanedione (5α- androstane-3,17-dione; 5α-dione), Androstenedione (androstene-3,17-dione; A4), Androsterone (5α-androstan-3α-ol-17-one; AST), 5α-dihydrotestosterone (5α-androstan-17β-ol-3-one; DHT), Drospirenone (17-Hydroxy-6β,7β:15β,16β-dimethylene-3-oxo-17α- pregn-4-ene-21 carboxylic acid, DRSP), dutasteride ((5α,17β)-N-[2,5- Bis(trifluoromethyl)phenyl]-3-oxo-4-azaandrost-1-ene-17-carboxamide), gestodene (4,15- estradien-17β-ethynyl-18-homo-17α-ol-3-one, GES), indomethacin (1-(4-Chlorobenzoyl)-5- methoxy-2-methyl-3-indoleacetic acid) and testosterone (4-androsten-17β-ol-3-one; T) were purchased from Sigma Aldrich (St. Louis, USA). 11-KetoAndrostenedione (4-androstene- 3,11,17-trione; 11KA4), 11-ketotestosterone (4-androsten-17β-ol-3,11-dione; 11KT), 11- keto-5α-dihydrotestosterone (5α-androstan-17β-ol-3,11-dione; 11KDHT) and 11- ketoAndrosterone (5α-androstan-3α-ol-11,17-dione; 11KAST) were purchased from Steraloids (Wilton, USA). testosterone-1, 2-D2 (T-D2) was purchased from Cambridge Isotope Laboratories (Andover, USA).

Androstanedione, bicalutamide, dexamethasone, dibutylphthalate, dihydrotestosterone (DHT), flutamide, hydroxyflutamide, levonorgestrel, lidocaine hydrochloride, 1-ethyl-3-(3-methylaminopropyl)carbodiimide (EDC), gluteraldehyde, hydroxylamine hydrochloride, N-hydroxysulfosuccinimide (Sulfo-NHS), potassium phosphate dibasic, pyridine (99.8%), sodium azide, sodium cyanoborohydride, sodium chloride, trizma base, calcium chloride, glycerol and sodium phosphate monobasic were purchased from Sigma–Aldrich (Stainhaim, Germany). HPLC grade Acetonitrile (ACN) and methanol (MeOH) were from POCh (Gli-wice, Poland). Human androgen receptor (AR) full length protein was from Abcam (Cambridge, UK).
Commercially available amine terminated magnetic beads (BcMag) (50 mg/mL, 1 μm diameter) of “sophistically coated iron oxide particles to provide primary amino groups”, were purchased from Bioclon Inc. (San Diego, CA, USA). A manual magnetic separator Dynal MPC-S was purchased from Invitrogen (Carlsbad, CA, USA). Solutions were prepared using purified water used in the study using a Milli-Q Water Purification System (Millipore, Bedford, MA, USA).