Changes of sperm tail morphology after kallikrein treatment

Kallikrein has been reported to act positively on sperm motility. Because sperm motility must be analyzed with regard to sperm tail morphology, this study examined whether changes of sperm motility after kallikrein treatment were accompanied by structural alterations of the midpieces and tails of spermatozoa. In 60 andrologic outpatients in whom a significant improvement of sperm motility was noted after treatment with kallikrein (600 U daily for 3 mo), sperm tail morphology was analyzed according to a recently proposed classification. The effect of kallikrein could be clearly attributed to a decrease of tail disturbances characteristic of epididymal dysfunction. Besides possible effects on spermatogenesis, kallikrein may influence the epididymal maturation of spermatozoa, leading to increased progressive motility.