ABSTRACT
Evidence has been provided these last few years that a phospholipase C is responsible for egg metabolism activation after fertilization. How the sperm activates this enzyme remains however to be determined. Two models have been proposed in recent litterature. In the first model, the sperm binds to a receptor on the egg plasma membrane, linked to a phospholipase C via a G-protein (Jaffe 1989). In the second model, egg activation is triggered by a sperm diffusible factor (Whitaker 1989). In the light of our own data, we review and discuss these different hypotheses, and present results suggesting that tyrosine kinase activity is involved in the chain of events which leads to egg activation.
