Acromegalic patients present with volume expansion and arterial hypertension but the renal sites and molecular mechanisms of direct antinatriuretic action of growth hormone (GH) remain unclear. Here, we show that acromegalic GC rats, which are chronically exposed to very high levels of GH, exhibited a decrease of furosemide-induced natriuresis and an increase of amiloride-stimulated natriuresis compared to controls. Enhanced Na⁺, K⁺-ATPase activity and altered proteolytic maturation of epithelial sodium channel (ENaC) subunits in the cortical collecting ducts (CCD) of GC rats provided additional evidence for an increased sodium reabsorption in the late distal nephron under chronic GH excess. In vitro experiments on KC3AC1 cells, a murine CCD cell model revealed the expression of functional GH receptors (GHR) and IGF-1 receptors coupled to activation of JAK2/STAT5, ERK and AKT signaling pathways. That GH directly controls sodium reabsorption in CCD cells is supported by i) stimulation of transepithelial sodium transport inhibited by GHR antagonist pegvisomant ii) induction of ENaC mRNA expression iii) identification of STAT5 binding to a response element located in the ENaC promoter, indicative of the transcriptional regulation of ENaC by GH. Our findings provide first evidence that GH, in concert with IGF-1, stimulates ENaC-mediated sodium transport in the late distal nephron, accounting for the pathogenesis of sodium retention in acromegaly.