The hormones vasopressin and aldosterone play key roles in the fine adjustment of sodium and water reabsorption in the nephron. One important molecular target of this regulation is the epithelial sodium channel (ENaC) which is essential for Na+-reabsorption in the distal tubule and the collecting duct. Functional channels consist of alpha-, beta- and gamma-ENaC-subunits encoded by different genes. In this study we investigated mRNA-specific post-transcriptional mechanisms under aldosterone- or dDAVP-dependent (V2 receptor agonist) expression of ENaC subunits in mouse kidney cortical collecting duct cells. In transcription experiments and polysome gradient analysis we observed that both hormones influence the expression rates of ENaC subunits at the level of transcription and mRNA translation. Our data indicate that post-transcriptional control of gene expression accounts to a significant part, especially for the alteration of gamma-EnaC expression. We demonstrate that aldosterone and dDAVP activate down-stream pathways acting on the synthesis of gamma-ENaC subunit by modulation of mRNA translation but not mRNA stabilization. By polysomal gradient analysis we show that certain RNA-binding proteins co-localize with gamma-ENaC mRNA in polysomes in a hormone dependent manner. The AU-rich element (ARE) binding proteins HuR, AUF1 and TTP were identified as dominant mediators in the alteration of gamma-ENaC synthesis. We verified the significance of our findings by applying different techniques such as RNA-affinity chromatography and subsequent MALDI-TOF-MS basedtrans-factor identification, co-immunoprecipitation, UV-crosslinking analysis and reporter-gene co-expression experiments. In summary, we show that post-transcriptional gene expression control is important for vasopressin and aldosterone mediated expression of ENaC.