Prostaglandins and Leukotrienes

This chapter is not intended for the prostaglandin (PG) specialist but, rather, for those not familiar with the PG field. It provides a brief overview of the biology of the eicosanoid family and how these local mediators may function in health and disease. The term eicosanoids (from the Greek eicosa, which means 20) was coined to describe the broad group of compounds derived from C20 fatty acids that, in turn, are derived from the essential dietary fatty acids. The predominant C20 fatty acid precursor for eicosanoid biosynthesis in most mammals is arachidonic acid (AA). These eicosanoids include the PGs and thromboxanes (TXs), leukotrienes (LTs), lipoxins (LPXs), and hydroxyeicosatetraenoic acids (HETEs). Because the biologic activity of eicosanoids is diminished rapidly in both tissues and the circulation, it is likely that they act locally at the tissue and organ level, where they may regulate regional blood flow and other metabolic activities. Moreover, their formation in various inflammatory sites indicates an important mediating role for these substances in diseased states. Indeed, eicosanoid inhibition by different classes of anti-inflammatory drugs underlines their importance in this regard. This chapter includes a brief historical background, together with a description of nomenclature, biosynthesis, and selected local actions of PGs and LTs. For those requiring more detailed information, see the references at the end of this chapter.