Cardiotonic steroids trigger non-classical testosterone signaling in Sertoli cells via the α4 isoform of the sodium pump

► The α4 isoform of the sodium pump alpha subunit is expressed in Sertoli cells. ► This subunit mediates signaling cascades that are induced by ouabain. ► The ouabain-triggered Src/cRaf/Erk1/2 signaling cascade results in CREB activation. ► This cascade matches the non-classical signaling cascade induced by testosterone. ► The results may help to unveil novel mechanisms associated with male fertility.