Using the fluorescent calcium indicator fura-2, forskolin was found to dose-dependently cause an immediate increase in the concentration of intracellular free calcium of porcine cauda epididymal sperm. This stimulatory effect of forskolin is due to the enhancement of Ca2+ uptake by the verapamil-sensitive transporter on the sperm plasma membrane and results in the promotion of the sperm capacitation and subsequent acrosome reaction.
