[Metabolism and action mechanisms of eicosanoids and platelet-activating factor in the kidney]

Recent advances in molecular biological studies on the metabolism and action mechanisms of lipid mediators: arachidonic acid metabolites (eicosanoids) and platelet-activating factor (PAF), are reviewed, in relation to their roles in the kidney. For the last decade, almost all the enzymes involved in three major arachidonic acid metabolic pathways; cyclooxygenase, lipoxygenase and epoxygenase pathways, have been purified and almost all of their cDNA have been cloned. Recently, cDNAs encoding three receptors for lipid mediators; PAF receptor, thromboxane A2/prostaglandin (PG) H2 receptor and a subtype of PGE2 receptor; EP3, were cloned. These advances have facilitated our knowledges of the physiological, pathophysiological roles of these lipid mediators in the kidney.