Main Entry: plate·let–ac·ti·vat·ing factor
Pronunciation: -"ak-t&-"vAt-i[ng]-
Function: noun
: phospholipid that isproduced especially by mast cells and basophils, causes the aggregation of blood platelets and the release of blood-platelet substances (as histamine or serotonin), and is a mediator of inflammation(as in asthma) —abbreviation PAF