Platelet-activating factor acetylhydrolase in the male reproductive tract: origin and properties

The properties and origin of platelet-activating factor acetylhydrolase- (PAF-AH)-like activity in the male reproductive tract were investigated. Seminal plasma (SP) and serum were obtained from normal donors and infertile patients while prostatic fluid (PF), seminal vesicle fluid (SVF) and vas deferens fluid were collected at autopsy. PAF-AH-like activity was found in all fluids tested. The specific activity of the enzyme in SP and PF was twice that of PAF-AH in serum and 15-fold higher than that in SVF and vas deferens fluid. In SP, PAF-AH-like activity was Ca(++)-independent, acid and heat labile, stable to freezing, not inhibited by phosphatidylcholine, but was inhibited by 10 mM disopropylfluorophosphate (DFP) and 13 mM phenylmethylsulfonylfluoride (PMSF). These data indicate that the properties of the enzyme in SP are similar to those reported for PAF-AH in serum. The variation in specific activity of PAF-AH in reproductive tract fluids suggest that there are either activators of PAF-AH in SP or inhibitors in one or several of the other reproductive tract fluids.