Objective: To search for the presence of platelet-activating factor (PAF) acetylhydrolase activity in human seminal plasma.
Design: Experimental.
Setting: Reproductive laboratory in a university-affiliated hospital research center.
Participants: Human male volunteers were selected on the basis of apparent normal health.
Results: Human seminal plasma contained significant levels of PAF-acetylhydrolase activity. Enzymatic hydrolysis of PAF displayed typical kinetics and was a calcium-independent process. Platelet-activating factor acetylhydrolase in seminal plasma was associated with a very high-density lipoprotein fraction. Enzymatic activity was independent of sperm count and motility.
Conclusion: Human seminal plasma contains significant levels of PAF acetylhydrolase. This enzyme may be an important factor in the regulation of PAF concentration and activity.