Figure 7.

Regulatory mechanism of the acrosome reaction (AR) and hyperactivation induced by progesterone (P). Dotted arrows indicate the regulatory signals of the AR induced by P. Arrows indicate the regulatory signals of hyperactivation induced by P. A high concentration of P stimulates Phospholipase Cδ (PLCδ) and induces the AR. A low concentration of P stimulates PLC and induces hyperactivation. AC, adenylate cyclase; CAMK, calmodulin‐dependent protein kinase; cAMP, cyclic adenosine monophosphate; IP3R, inositol 1,4,5‐trisphosphate receptor; PC, phosphatidylcholine; PI, phosphatidylinositol; PKA, protein kinase A; PLC, phospholopase C; PR, progesterone receptor; PTK, protein tyrosine kinase.