EFFECTS OF PLATELET-ACTIVATING-FACTOR ON HUMAN SPERM FUNCTION IN-VITRO

The direct effects of platelet activating factor (PAF) and the specifi c PAF receptor antagonist, CV-3988, on the fertilizing ability of huma n spermatozoa were investigated. PAF (10(-7)-10(-11) M) increased the human sperm penetration rates in a sperm penetration assay at all dose s > 10(-11) M. In contrast, treatment of the spermatozoa with 10(-5) C V-3988 caused a significant decrease in human sperm penetration of zon a-free hamster oocytes and adversely affected sperm motility after 24 h of incubation. This suppression was reversed by the addition of PAF. The acrosome reaction was also enhanced by PAF treatment of spermatoz oa but this effect was not observed in calcium-free medium. While 10(- 5) M CV-3988 decreased the acrosome reaction, the inhibition was also reversed by the addition of PAF. These results suggest that PAF may ha ve a direct role in the fertilizing capacity of human spermatozoa. The se findings also suggest that PAF may have a clinical application in a n in-vitro fertilization programme.