Hyaluronidase activity in untreated human semen and following laboratory manipulations

Hyaluronidase activity was examined in 104 oligospermic and normospermic human semen specimens promptly after liquefaction, after repeated cycles of washings with a solution containing 1.3 M sucrose and 0.15 M NaCl, and after freezing and thawing. We assessed enzyme activity by measuring areas of the digestion of substrate (hyaluronate). After washing the oligospermic and normospermic semen specimens twice 34%-43% enzyme activity was still present in the sedimented sperm as compared to the initial values. Following additional washings no enzyme activity could be detected. Freezing and thawing of semen increased enzyme activity by 40%-50%, respectively, after the second cycle whereas further treatment did not increase the enzyme activity rate. It is suggested that two types of hyaluronidase are present in human spermatozoa, differing in membrane-binding properties which would be connected with their localization in the acrosome.