Acceleration of acrosome reaction in hamster spermatozoa by lysolecithin

When hamster spermatozoa were preincubated for 1–2 hr in Ca 2+ ‐containing medium and then exposed to lysolecithin (LC), large proportions of the spermatozoa underwent acrosome reactions within 15 min. These acrosome‐reacted spermatozoa were capable of fertilizing eggs. The earliest visible sign of the reaction, wrinkling of the acrosomal cap, seen by 30 sec after exposure to LC. The reaction in many spermatozoa was completed within the next 30 sec.