The rapid development in the knowledge about the synthesis and metabolism of the various products derived from arachidonic acid is a continuous chal lenge for those who intend to measure these substances in biological fluids. The confusion which still exists about their possible role in some physiolo gical and pathological situations is partly due to the methodological pro blems related to the estimation of these metabol ites in subnanogram quanti ties. This concern has inspired the Commission of the European Communities to sponsor a first workshop on the 'Clinical Application of Assay Methods for Prostaglandins 'which was held in Brussels at the end of 1976. During that meeting it became clear that progress in the qualitative and quantitative analysis of the prostaglandins could only be made by a permanent reevalua tion of the existing techniques and therefore the possibility should be r created for experts in the field to meet regularly and to discuss the value of the newly developed assay methods. Since then exciting new discoveries have been made in this rapidly ex r panding area: in October 1976 the birth of the prostacycl in area was an nounced and in May 1979 a possible structure and biosynthetic pathway for slow-reacting substance of anaphylaxis (SRS-A) was presented.
