Effects of platelet activating factor on capacitation and acrosome reaction in mouse spermatozoa

Platelet activating factor (PAF) plays an important role in mammalian repro duction. The aim of this study was to investigate the effects of PAF on cap acitation and acrosome reaction of mouse spermatozoa by chlortetracycline ( CTC) fluorescence assay and coomassie blue staining. The percentage of capa citated mouse spermatozoa was increased (P < 0.05) by incubation with 50 ng /ml PAF for 20-120 min. The peak response occurred between 80 to 100 min of exposure to PAF. In contrast, the effects of PAF on acrosome reaction may be not receptor-mediated since lyso-PAF had the same effects. Ionophore A23 187 stimulated an increase in acrosome-reacted spermatozoa of PAF-treated s permatozoa, but not of lyso-PAF-treated ones. These results suggest that PA F mainly acts on sperm capacitation, Mol. Reprod. Dev. 56:436-440, 2000. (C ) 2000 Wiley-Liss, Inc.