Starvation induces an increase in intracellular calcium and potentiates the progesterone‐induced mouse sperm acrosome reaction

Abstract We have recently reported two different methodologies that improve sperm functionality. The first method involved transient exposure to the Ca 2+ ionophore A 23187 , and the second required sperm incubation in the absence of energy nutrients (starvation). Both methods were associated with an initial loss of motility followed by a rescue step involving ionophore removal or addition of energy metabolites, respectively. In this work, we show that starvation is accompanied by an increase in intracellular Ca 2+ ([Ca 2+ ] i ). Additionally, the starved cells acquire a significantly enhanced capacity to undergo a progesterone‐induced acrosome reaction. Electrophysiological measurements show that CatSper channel remains active in starvation conditions. However, the increase in [Ca 2+ ] i was also observed in sperm from CatSper null mice. Upon starvation, addition of energy nutrients reversed the effects on [Ca 2+ ] i and decreased the effect of progesterone on the acrosome reaction to control levels. These data indicate that both methods have common molecular features.