Mice were treated with daily oral drug (vehicle, vamorolone, eplerenone, or spironolactone) and implanted with osmotic pumps that secreted either aldosterone or vehicle for 6 wk. Kidney size was assayed as an epithelial MR target tissue, where aldosterone-specificity of the MR is maintained through expression of the glucocorticoid-inactivating enzyme HSD11B2. (A) Representative kidney images are provided. (B) Aldosterone induced an increase in kidney mass in both wild-type and mdx. This was prevented in mdx by all three MR antagonists. (n ≥ 8 per group; ***P < 0.0005, ANOVA with post hoc test versus mdx + aldosterone in red; ##P < 0.005, t test comparing WT groups; V = Vamorolone, E = Eplerenone, S = Spironolactone).