Platelet-activating factor and related lipid mediators

Platelet-activating factor (PAF) Is a phospholipid with potent, diverse phy siological actions, particularly as a mediator of inflammation. The synthes is, transport, and degradation of PAF are tightly regulated, and the bioche mical basis for many of these processes has been elucidated in recent years . Many of the actions of PAF can be mimicked by structurally related phosph olipids that are derived from nonenzymatic oxidation, because such compound s can bind to the PAF receptor. This process circumvents much of the bioche mical control and presumably is regulated primarily by the rate of degradat ion, which is catalyzed by PAF acetylhydrolase. The isolation of cDNA clone s encoding most of the key proteins involved in regulating PAF has allowed substantial recent progress and will facilitate studies to determine the st ructural basis for substrate specificity and the precise role of PAF in phy siological events.