Aim: To investigate a simple method for assaying acrosin activity for the e
valuation of male fertility. Methods: The acrosin activity of 7.5 x 10(6) s
perm. without seminal plasma and acrosin activity inhibitors was assayed us
ing N-alpha -benzoyl-DL-arginine-p-nicroanilide (BAPNA) and detergent (Trit
on X-100) as substrate. Results: The acrosin activity of 60 normal fertile
men (35 +/- 10 mu IU/10(6) sperm) was higher than that of 168 infertile men
(16 +/- 8 mu IU/10(6) sperm) (P <0.01). It was indicated that there was a
significant positive correlation between the acrosin activity and the sperm
motility (r<greater than or equal to>0.6534, P < 0.01) and a significant n
egative correlation between the sperm malformed rate and the WBC number ( r
<less than or equal to> -0.5426, P < 0.01). The temperature and time of in
cubation and the sperm concentration could influence the assay results. Con
clusion: Acrosin activity is an important index for the evaluation of male
fertility. The approach developed by the authors is a simple method for the
determination of acrosin activity.