Cardiotonic steroid ouabain stimulates steroidogenesis in Leydig cells via the α3 isoform of the sodium pump.

•We demonstrate hormone-like actions of ouabain on a Leydig cell line.•We show ouabain-induced activation of Erk1/2, CREB and ATF-1.•Ouabain triggers mobilization of LDs and PLIN2 and stimulates steroidogenesis.•Silencing expression of the α3 isoform of the sodium pump prevents all the above.•The results imply that ouabain-induced signaling might be part of male physiology.