Assessment of sperm function in fertile and infertile men

The sperm function of fertile men (control), infertility patients (experimental), and men with varicocele were compared. The bioassays used were the follicular fluid-induced acrosome reaction, the binding to the zona pellucida, and the penetration of zona-free hamster oocytes. The percentage (mean +/- SEM) of reacted spermatozoa was 35 +/- 3 in the control, 22 +/- 1 in the experimental, and 22 +/- 3 in the varicocele. The minimum value of acrosome reaction in control men was 20%. The mean number of zona-bound spermatozoa was 250 +/- 30 in the control, 160 +/- 28 in the experimental, and 196 +/- 44 in the varicocele. The minimum number of zona bound spermatozoa in control men was 50. The mean number of hamster oocytes penetrated was 50 +/- 8 in the control, 19 +/- 3% in the experimental, and 10 +/- 3 in the varicocele. The minimum number of oocytes penetrated in control men was 6%. In the experimental group, 22 men had a normal sperm function, 58 had 1 or 2 bioassays below the minimum (relative dysfunction), and 10 had all bioassay below the minimum (abnormal sperm function). The results of these bioassays could help to reclassify the infertile men in several subgroups.