A review of the effect of platelet-activating factor on male reproduction and sperm function

Abstract

Eight to 10 million couples in the United States are infertile. Male infertility is the primary diagnosis in approximately 25% of these couples and is a contributing factor in an additional 20% of these couples. There are several prerequisites (ie, production of normal, motile sperm capable of undergoing capacitation and the acrosome reaction) that must be met for male fertility. Defects in any of these will result in infertility. PAF is present in spermatozoa and is positively correlated with fertility. Spermatozoa have a specific PAF receptor, as demonstrated by reports that the receptor is localized to the midpiece and equatorial region. Abnormal spermatozoa demonstrate a different pattern of PAF receptor locations, and PAF antagonists inhibit sperm motility and fertilization rates. Further, exogenous exposure to PAF enhances sperm motility, forward progression, fertilization, and implantation and pregnancy rates. The exact mechanism of PAF action on spermatozoa is uncertain; however, it plays a critical role in normal sperm function. PAF appears to mediate sperm motility by inducing the formation of inositol triphosphate and diacylglycerol and by increasing intracellular calcium (Lapetina, 1982; Ahmed et al, 1994; Roudebush et al, 1997). The reproductive significance of PAF activity in spermatozoa and fertility, including the role of PAF in the establishment of pregnancy, requires further study.