platelet-activating factormedical dictionary


Potent phospholipid activator and mediator of many leucocyte functions, including platelet aggregation, inflammation, and anaphylaxis.

It is produced in response to specific stimuli by a variety of cell types, including neutrophils, basophils, platelets, and endothelial cells. Several molecular species of platelet-activating factor have been identified which vary in the length of the O-alkyl side chain. It is an important mediator of bronchoconstriction.

Synonyms: platelet-aggregating factor.

Acronym: PAF

(20 Sep 2002)