A spectrophotometric assay is described which, due to improved extraction conditions, allows quantitative determination of enzymatically active, non-
zymogen acrosin,
proacrosin and total
acrosin activity from human sperm acrosomes.
Acrosomal proteinase activity is assessed by
acid extraction of the sperm pellet and the
suspension medium before and after snap-freezing, followed by
zymogen autoactivation. Release of
acrosin from the acrosome can be used as a sensitive
biochemical marker to characterize acrosomal membrane stability, severe disturbance of which may be the cause of impaired male fertility.
Acrosin activities in different populations of semen specimens are reported and compared to data available in the literature. Different degrees of acrosomal membrane alterations are observed in men with
oligozoospermia, tetratozoospermia and polyzoospermia. Particularly in
oligozoospermia, a significant increase of active, non-
zymogen acrosin points to severe acrosomal membrane alterations and, in addition, to a premature activation of
proacrosin, which may impair fertilization in certain individuals. Finally,
acrosin activity is shown to be significantly influenced by the time of sexual abstinence. It is concluded that determination of
acrosin may be a useful
indicator of the fertility potential in men.