Inhibition of fertilization in the hamster by sodium aurothiomalate, a hyaluronidase inhibitor

Abstract

Summary. Sodium aurothiomalate, a low molecular weight inhibitor of hyaluronidase, blocked in-vitro fertilization in hamsters at the level of the zona pellucida: concentrations of 25–250 pg inhibitor/ml prevented fertilization of cumulus-intact and cumulus-denuded eggs. Fertilization of zona-free ova was not affected. In-vivo fertilization was also reduced (from 100% in controls to 37·5%) by 10 mg inhibitor/ml added to an epididymal sperm suspension before artificial insemination into the uterus. These findings suggest that hyaluronidase may play a role in zona penetration or that sodium aurothiomalate blocks sperm penetration of the zona by inhibiting an enzyme(s) other than hyaluronidase.