Presence of platelet-activating factor in rhesus (Macaca mulatta) spermatozoa

Platelet-activating factor [1-O-alkyl-2-acetyl-sn-glycero-phosphocholine; P AF] is a unique signaling phospholipid which has been implicated in a numbe r of biological activities (e.g., reproduction). PAF has been detected in t he spermatozoa from a number of laboratory and domestic species, including, but not limited to, rabbit, bovine, and the mouse. The concentration of PA F is inversely related to human (Homo sapien) spermatozoal quality. Additio nally, PAF levels are significantly higher in Bolivian squirrel monkey (Sai miri sciureus) spermatozoa obtained during the breeding season than spermat ozoa obtained during the nonbreeding season. There are no reports on the pr esence of PAF in rhesus (Macaca mulatta) spermatozoa. Therefore, the primar y objective of this study was to detect the presence of PAF in rhesus sperm atozoa. A second objective was to determine if PAF spermatozoa levels diffe r between animals housed individually (single-caged) versus free-ranging (o pen corrals). Semen were collected from mature rhesus via electro-ejaculati on. Spermatozoa were washed free of ejaculatory plug and quick frozen in PB S. Endogenous lipids were extracted from thawed spermatozoa and ejaculatory plugs then assayed for the presence of PAF by [I-125]-radioimmunoassay. PA F was not detected in any ejaculatory plugs. PAF levels were significantly higher (P < 0.01) in spermatozoa obtained from free-ranging males (mean: 1. 16 pmol/10(6) spermatozoa) than males housed individually in single cage un its (mean: 0.53 pmol/10(6) spermatozoa). PAF was present in rhesus spermato zoa. Additionally, PAF levels were higher in spermatozoa obtained from corr al-housed animals. Additional studies are warranted to elucidate the role o f PAF in spermatozoa function.