Dynamic changes of intracellular zinc ion level during maturation, fertilization, activation, and development in mouse oocytes.

Although it is well known that calcium oscillations are required for fertilization in all mammalian species studied to date, recent studies also showed the ejection of zinc into the extracellular milieu in a series of coordinated events, called "zinc spark," during mammalian fertilization. These results led us to the hypothesis that a zinc ion-dependent signal is important for oocyte maturation, fertilization (activation), and further embryonic development. In this study, we evaluated the amounts and localization of intracellular zinc ions during maturation, fertilization, activation, and embryonic development in mouse oocytes.