ABSTRACT
Platelet activating factor (PAF) is a biologically active ether-linked glycerophospholipid that activates platelets seems to serve as a critical mediator in diverse biological processes such as inflammation, anaphylaxis, and neuronal development. Alkyl and alk-1-enyl glycerolipids were identified and the precise chemical structure of these compounds reported between 1915 and 1924. However, it took about 50 years to establish the biosynthetic pathways involved in the synthesis of these ether-linked glycerophospholipids. The purpose for the existence of these two different pathways for the biosynthesis of PAF is not clear. However, this is not an unique situation in lipid metabolism. The mechanism by which the various signals stimulate the acetylation of lyso-PAF is not well understood, although there is evidence in favor of a phosphorylation-dephosphorylation process. PAF stimulates many different target cells and, in each case, induces a set of specific biological responses. Of particular interest is the question of whether the activation of target cells by PAF is a receptor-mediated event.
