Induction of the cortical reaction in hamster eggs by membrane-active agents

Abstract

Fusion of capacitated spermatozoa with the vitelline membrane, but not actual penetration, appears to initiate the cortical reaction in golden hamster [Mesocricetus auratus] eggs. The reaction can be artificially induced by the application of positively charged particles to the vitelline surface, a situation which may normally be prevented by the zona pellucida. Exposure of hamster eggs to neuraminidase, to lectins (concanavalin A and phytohemagglutinin-P), to a monovalent ionophore (boromycin) and to 1,3-bis(4-chlorocinnamylideneamino)guanidine elicited a cortical granule discharge resulting in a block to fertilization. These agents all appeared to act by inducing depolarization of the vitelline membrane.