Although initial attempts have been made to characterize molecules involved in sperm-oviduct binding, still very little is known about the mechanisms involved in sperm release after ovulation. Hormonal changes at the time of ovulation are likely to affect sperm release. Preliminary data suggested that these changes induce secretory activity in the oviduct, most predominantly in the ipsilateral oviduct to the ovulatory follicle. Furthermore, follicular fluid will enter the oviduct at ovulation.
Both the oviduct secretory products and components in the follicular fluid induce sperm capacitation, support sperm motility, induce acrosome reaction, and enhance affinity for the zona pellucida. In addition, proteins from oviductal fluid can bind to sperm, thus affecting sperm motility, viability, and fertilizing ability. Follicular and oviductal fluids are rich sources of glycos-aminoglycans (GAG) that may affect sperm capacitation in bovine. In fact, follicular fluid is included in in vitro fertilization (IVF) media to increase the capacitation of sperm cells and the developmental capacity of the oocytes to be fertilized.