Na,K-ATPase is an oligomeric protein composed of an essential α- and β-subunits and an optional third subunit belonging to the FXYD proteins which are more tissue specific regulatory subunits of the enzyme (Lingrel & Kuntzweiler, 1994; Geering K 2006). Four isoforms of α-subunit (α1–α4) and three isoforms of β-subunit (β1–β3) have been identified so far, which are encoded by different genes (Blanco G 2005). Na,K-ATPase functions as an ion pump, hydrolyzing one molecule of ATP to pump three Na+ out of the cell in exchange for two K+ entering the cell per pump cycle (Kaplan JH 2002). Mineralocorticoids control Na+ reabsorption by regulating the activity of Na,K-ATPase in diverse mammalian tissues such as kidney, heart, brain, vascular smooth muscle and skeletal muscle (reviewed by Li Z & Langhans SA 2015). In kidney collecting duct cells aldosterone controls Na+ reabsorption in the short term by coordinately regulating the apical cell surface expression of luminal epithelial sodium channels ENaC and basolateral cell surface expression of the Na,K-ATPase (Summa V et al. 2001, 2004; Blot-Chabaud M et al. 2001; Mick VE et al. 2001).