MR/GR association and aldosterone effect in human platelets. (A) Washed platelet extracts were immunoprecipitated with anti-GR antibodies that coprecipitated MR; the same did not occur for PBMC extracts (prepared from the same donors) or when an IgG2 isotype was used. Blots are representative of 3 distinct determinations. (B) Human PRP was incubated with 10 μM aldosterone (Aldo) before addition of 4 μm ADP; alternatively (right-hand panel), dexamethasone (10 μM) was added after Aldo. (C) Cumulative data from the experiments depicted in panel B. Data are mean ± SEM of 3 experiments with distinct platelet donors and performed in duplicate. ^*P < .05 versus control ADP-induced platelet aggregation.