Notes: Oxidized low-density lipoprotein (oxLDL) particles contain low molecular weight species which promote the differentiation of monocytes and activate polymorphonuclear leukocytes.{8499} One of these substances was recently isolated and purified from oxLDL, and identified as azelaoyl PC.{8953} Butanoyl PAF is a closely related compound which retains at least 10% of the agonist potency of platelet-activating factor (PAF) itself.{8533} Further, butanoyl PAF is present in oxLDL in amounts more than 100 times greater than enzymatically generated PAF. Butanoyl PAF is therefore one of the important signalling molecules present in oxLDL.