Epithelial Na+ absorption can be controlled by hormones / neurotransmitters that act via cAMP / PKA (e.g. vasopressin, adrenaline) and there is evidence (e.g. Vasquez et al., 2008) that the hormone-induced activation of this pathway leads to increased activity of serum / glucocorticoid-regulated kinase 1 (SGK1). SGK1 can phosphorylate residues (Ser221, Thr246, Ser327) within Nedd-4/2, a ubiquitin ligase that targets epithelial Na+ channel subunits (α-, β- and γ-ENaC) for internalization / degradation (Lang et al., 2006). It has therefore been suggested that, by activating SGK1, PKA might prevent the Nedd-4/2-dependent internalization of ENaC leading to increased Na+ transport. However, not all data support this hypothesis since others have suggested that PKA can directly phosphorylate Nedd-4/2 and thus control Na+ absorption via a mechanism that is independent of SGK1 (Snyder et al., 2004). The present study therefore explores the effects of an SGK1 inhibitor (GSK65094) upon the responses to cAMP-elevating drugs in a Na+ absorbing, human airway epithelial cells (H441). Western analyses using phospho-specific antibodies showed that 20 min exposure to cAMP-elevating drugs increased the abundance of the Ser221-, Thr246- and Ser327-phosphorylated forms of Nedd-4/2 (Fig. 1A). This accords well with data presented by Snyder et al. (2004) although we find that these cAMP drugs also increased the overall abundance of Nedd-4/2 itself (Fig. 1A). Analysis of surface-exposed protein showed that cAMP-elevating drugs also increased the amount of β- and γ-ENaC in the membrane (Fig 1B), whilst electometric studies revealed increased of amiloride sensitive Na+ absorption (Fig 1C). GSK65094 (10 µM, 3 h) reduced the phosphorylation status of all three residues in Nedd-4/2 although some phosphorylation of Thr246 persisted in the presence of this SGK1 inhibitor (Fig. 1A). GSK65904 also reduced the membrane abundance of all three ENaC subunits (Fig 1B) and suppressed the basal rate of Na+ transport (Fig. 1C), findings consistent with the view that SGK1 is important to the control of ENaC (Lang et al., 2006). However, cAMP clearly evoked phosphorylation of Nedd-4/2-Ser221, -Ser327 and -Thr246 in GSK65904-treated cells, and these responses were accompanied by increases in the membrane abundance of α-, β- and γ-ENaC (Fig 1B), and an unambiguous stimulation of electrogenic Na+ transport (Fig 1C). Clear responses to cAMP therefore persist when SGK1 is inhibited indicating that the cAMP / PKA-dependent control of Na+ absorption does not involve this protein kinase (Snyder et al., 2004; Mansley & Wilson, 2010).