Presence of platelet-activating factor in blood from humans and experimental animals. Its absence in anephric individuals.

Blood from humans and experimental animals was examined for the presence of platelet-activating factor. The procedure included a rapid extraction of the samples and a purification of the lipid content by thin layer chromatography. The chemical characterization was performed by phospholipases' treatment and high performance liquid chromatography. Rats contained the highest concentrations of platelet-activating factor and rabbits the lowest. Five anephric patients undergoing support hemodialysis had undetectable blood levels and the same finding was observed in six rats in which surgical nephrectomy was performed. Based on these data we suggest: 1) Low amounts of platelet-activating factor can be present in blood under normal conditions. 2) Kidney tissue seems to play a role in the formation of the platelet-activating factor that can be detected in blood under these conditions.