Prostaglandins and their receptors

Euler’s description that seminal vesicles contain a prostate-derived hypotonic activity [1] causing various pharmacological effects initiated an intense search for the active entities, the prostaglandins. This marks the beginning of the study of paracrine hormonal regulation in tissues. Research revealed that arachidonic acid, which is cleaved from the cell membrane by phospholipases, is the precursor of the prostaglandins (on which we concentrate in this review) and of the structurally related leukotrienes and lipoxins (Fig. la).