Calcium-induced dehiscence of cortical granules in Xenopus laevis oocytes.

Microinjection of 0.1 microgram of Ca++ into Xenopus laevis oocytes induces breakdown of the cortical granules. The cortical granules disappeared in both full grown (Stage VI) and small growing (Stage IV) oocytes. Microinjection of Mg++, K+, or Na+ had no effect on cortical granules in either Stage IV or Stage VI oocytes. Small quantities (0.03 microgram) of Ca++ induced dehiscence of the cortical granules only in proximity to the injection site.