Release of hyaluronidase and beta-N-acetylhexosaminidase during in vitro incubation of hamster sperm.

Previous studies have shown that hamster sperm release a significant amount of hyaluronidase before and independently of the normal acrosome reaction. In this study, we have used improved methods for in vitro incubation to investigate the time course of the release of hyaluronidase and hexosaminidase from hamster sperm. When hamster sperm are incubated in medium which allows capacitation, 34 to 47% of the total mechanically extractable hyaluronidase and 34 to 51% of beta-N-acetylhexosaminidase are released into solution prior to and independently of the normal acrosome reaction (ARx). An additional 40 to 50% of the hyaluronidase and 34 to 51% of the hexosaminidase are released at the time of the normal ARx. Control experiments indicate that the early release is not due to the presence of dead sperm in culture and that the normal ARx is required for the second release. Increasing amounts of TCA-precipitated bovine serum albumin in the culture medium stimulated the early (1 hr) release of both enzymes. The data are consistent with the ideas that a significant amount of both enzymes is released from the sperm surface by 1 hr of incubation and that about the same amount of each enzyme is released during the normal ARx. Hyaluronidase and hexosaminidase release at the time of the acrosome reaction was measured for the first time using hamster sperm. The biphasic release of these enzymes may indicate that they have a dual function in fertilization and may help explain how sperm can penetrate the cumulus and corona radiata without undergoing an acrosome reaction.