Figure S1. An active metabolite of deflazacort shows no activity in MR reporter assays.

To determine if an active metabolite of deflazacort showed a lack of MR activity consistent with deflazacort, stable MR reporter cells were treated with 21-desacetyl deflazacort, prednisolone, or spironolactone. Used as controls here, prednisolone activated the MR as an agonist, and spironolactone acted as an antagonist to inhibit MR induction by aldosterone. Consistent with deflazacort, we found that the metabolite 21-desacetyl deflazacort avoided MR interaction. (A) Agonist activity was assayed by treating cells with each drug alone in increasing concentrations. (B) Antagonist activity was assayed by pretreating cells with each drug, then adding aldosterone (natural MR agonist) and assaying MR activity 6 h later. (Pred = Prednisolone, 21-Defl = 21-Desacetyl deflazacort, Spiro = Spironolactone).