Involvement of Esterases in Sperm Penetration of the Corona Radiata of the Ovum

During fertilization the spermatozoon must penetrate several layers surrounding the ovum prior to actual gamete fusion. It has been previously reported that acrosomal extracts of rabbit spermatozoa will disperse the cumulus layer, the corona radiata, and the zona pellucida from rabbit ova. The data presented here demonstrate that the esterolytic activity present in sperm acrosomes is involved in the dispersal of the corona radiata and thus in the penetration of the intracellular cement of the corona radiata during the fertilization process. Cumulus free ova have been shown to be subject to dispersal of corona radiata cells by the action of alkaline buffers. This in conjunction with the observation that the corona is dispersed by esterolytic activity is indicative of an ester linkage functioning in the macromolecular cementing substance in the intracellular matrix of the corona radiata of rabbit ova.