Progesterone primes zona pellucida-induced activation of phospholipase A2 during acrosomal exocytosis in guinea pig spermatozoa

During interaction with the oocyte, sperrnatozoa are stimulated to undergo exocytosis of the aerosome, a process essential for fertihzation. Two main agonists of exoeytosis have been identified in the oocyte vestments : progesterone (P4), which is trapped in the matrix of the cumulus oophorus