Medroxyprogesterone acetate (MPA), a widely used synthetic progestational contraceptive, occasionally leads to Cushingoid side effects such as hypertension, fluid retention and centripetal obesity. We investigated the effect of MPA on classic mineralocorticoid target genes, ENaC and sgk1, in the collecting duct. In adrenalectomized mice, aldosterone, dexamethasone and MPA increased ENaC mRNA levels in kidney cortex. MPA and dexamethasone, but not progesterone, dose-dependently increased ENaC and sgk1 mRNA in M-1 and in MDCK-C7 cells, both collecting duct cell lines. The stimulatory effect of MPA and dexamethasone on ENaC expression was inhibited by RU38486, a combined glucocorticoid receptor (GR) and progesterone receptor (PR) antagonist, but not by Org31710, a pure PR antagonist. MPA and dexamethasone dose-dependently increased ENaC promoter-driven luciferase activity in M-1 cells, which was not inhibited by Org31710, indicating that MPA regulates ENaC in a PR-independent manner. When tested in HT29 cells, MPA could only stimulate ENaC driven reporter activity when GR was co-expressed, confirming the requirement for functional GR in the transcriptional effect of MPA. The activation of steroid receptors such as GR can explain the apparent glucocorticoid effects of MPA, independent of PR activation.