Extracellular ATP is a potent signaling molecule that regulates different biological activities including proliferation, differentiation as well as cell death. Several studies have implicated extracellular ATP as a mitogenic agent in various cells in vitro. Herein, we aimed to investigate the involvement of ATP in mitogenic processes in vivo via stimulation of P2X7Rs in rat kidney. Results from the current study showed that administration of ATP caused rapid activation of ADAM-17 with subsequent phosphorylation of EGFR and ERK-1/2. Cyclin B1 expression in rat kidney was also increased following ATP administration. Interestingly, a marked decrease in renal ADAM-17 level as well as EGFR and ERK-1/2 phosphorylation was noticed when the animals were pretreated with the purinergic P2X7R antagonist, A 438079 before ATP administration. Moreover, ATP administration significantly increased serum levels of NO, an effect that was significantly ameliorated by A 438079 pretreatment. Collectively, current findings demonstrate the ability of ATP to activate the ADAM-17-mediated EGFR/ERK-1/2 phosphorylation and to enhance the expression of the cell proliferation gene cyclin B1, an effect that is largely mediated via P2X7Rs and involves NO modulation. Thus the safety of ATP supplementation as an ergogenic aid for muscle building and performance enhancement should be reassessed.