Estimation of hyaluronidase activity of human semen and its relationship with sperm density by means of a simplified method.

Abstract Hyaluronidase activity was examined in 109 specimens of human semen of various sperm densities, seminal plasma, and spermatozoa sedimented by centrifugation. We used a modification of a method originally devised for estimation of hyaluronidase activity in Clostridia and which was bases on measurements of the area of hyaluronate digestion in agar plates. Enzyme activities in both semen and seminal plasma increased with increase in sperm density. The activity in seminal plasma, which appeared promptly after liquefaction and represented enzyme released from spermatozoa, ranged from 31% to 61% of the activity in semen. Activities of spermatozoa in sediments exhibited lower values than those calculated for sperm of whole semen, possibly due to leakage. Both activities, calculated per million sperm cells, gradually increased with decrease in sperm density. The possibility that with severe oligozoospermia the acrosome may become less prone to enzyme release or that the initial activity per cell may increase is discussed. These phenomena would represent additional characteristics of oligozoospermia.