The modulation of androgen metabolism by estradiol, minocycline, and indomethacin in a cell culture model

Background: This investigation attempts to clarify the proanabolic effects of minocycline and indomethacin by studying their effects on androgen metabolism and mediation by estradiol. A cell culture model was used with androgen substrates because of the proanabolic effects of androgen metabolites. Methods: Monolayer cultures of human gingival fibroblasts (HGF) derived from 6 patients were incubated in duplicate with 14C- testosterone or 14C-4-androstenedione as substrates and optimal concentrations of estradiol (E-1,E-3 mug/ml) and minocycline (M-25 mug/ml) or indomethacin (I, 1 mug/ml) alone and in combination (E-1,E-3+I-1 or E-1,E-3+M-25 mug/ml); similar experiments were carried out with human oral periosteal fibroblasts (HPF), M, 1, E, and the combinations. At the end of a 24-hour incubation period in Eagle's MEM, the medium was solvent extracted with ethyl acetate and the metabolites were separated by TLC in a benzene:acetone solvent system (4:1 v/v). The separated metabolites were quantified using a radioisotope scanner. Results: Both androgens were metabolized to 5alpha-dihydrotestosterone (DHT) and 4-androstenedione (4-A) or testosterone (T) at baseline and in response to the agents tested, by HGF and HPF. With HGF, there were significant increases in the yields of DHT and 4-A or T in response to M, E, and M+E, resulting in 50% to 2.4-fold increases in these metabolites over control incubations (n = 6; P