THE RELEASE OF HYALURONIDASE FROM CAPACITATING HAMSTER SPERMATOZOA

Abstract

Summary. The release of acrosomal hyaluronidase from hamster spermatozoa capacitating in test-tubes was measured. In order to do this, a colorimetric hyaluronidase assay of increased sensitivity was developed, based upon the finding that an albumin—substrate complex was hydrolysed much more rapidly than hyaluronic acid alone. To estimate the degree of morbidity of the sperm samples, cytoplasmic lactic dehydrogenase loss into the media was monitored. This loss did not correlate with the percentage of motile spermatozoa, but was almost identical to the amount of hyaluronidase appearing in the medium when the spermatozoa were incubated in non-capacitating Tyrode's solution. Sperm hyaluronidase release, but not lactic dehydrogenase loss, was elevated by the addition of serum albumin in the presence or absence of human serum dialysate. This hyaluronidase release was magnified when heat-detoxified human serum was used to capacitate the spermatozoa. The relationship of these findings to capacitation-associated acrosome vesiculation and detachment is discussed.