Activation of hamster eggs by pricking

When mature unfertilized eggs of the golden hamster were picked with a glass needle, nearly 80% of them were activated. The diameter of needle was of critical importance for the successful induction of activation. It appeared that extracellular calcium was not necessary for the establishment (reception) of stimulation by pricking but was necessary for later phases of activation. The possible mechanisms by which pricking with a needle triggers the activation of the egg were compared with the mechanisms by which divalent ionophore induces activation.