Platelet-Activating Factor Levels (Ligand and Receptor) Content In Motile and Non-Motile Spermatozoa.
Roudebush WE, Zhu J, Massey JB, Elsner CW, Toledo AA, Mitchell-Leef D, Kort HI.
Reproductive Biology Associates, Atlanta, GA, USA.
Introduction: Platelet-activating factor [1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine; PAF] is a unique signaling phospholipid which has pleiotropic biological properties in addition to platelet activation. PAF-ligand and PAF-receptor mRNA are both present in sperm. Platelet-activating factor plays a significant role in sperm motility, fertilization and subsequent preimplantation embryo development.
Objective: To determine the activity level of PAF (ligand and receptor transcript) content in motile and nonmotile sperm.
Design: Comparison of PAF activity levels (ligand and receptor mRNA) between motile and nonmotile sperm.
Methods: Sperm samples were separated by density centrifugation into motile and nonmotile populations. PAF-ligand levels in sperm were measured via a PAF specific RIA. PAF-receptor mRNA expression levels in sperm were determined by semi-quantitated RT-PCR.
Results: The PAF-ligand was detected in all sperm samples. The amount of PAF-ligand in the nonmotile sperm population (0.94 pM/million cells) was significantly higher (P<0.01) than the nonmotile sperm population (6.8 aM/million cells).
Conclusion: There is an inverse relationship between PAF-ligand content in sperm, nonmotile sperm have more PAF than motile sperm. However, nonmotile sperm have a significant reduction of PAF-receptor mRNA. Nonmotile sperm may have more PAF-ligand due to their inability (lack of PAF-receptors) to utilize the compound.