AVPR2 and autosomal dominant polycystic kidney disease: Multiple signaling pathways have been found to be dysregulated in ADPKD with increased intracellular cyclic adenosine monophosphate (cAMP) concentration potentially as a consequence of vasopressin V2-receptor activation being a very prominent example that resulted in the identification of tolvaptan as a first treatment option of ADPKD [9,10,11] Increased intracellular cAMP concentrations also result in activation of the extracellular-signal regulated kinase and mitogen-activated protein kinase pathway (ERK/MAPK pathway) [47,48].