Prostaglandins (PGs) and related eicosanoids are signal moieties derived from arachidonic acid and two other C20 polyunsaturated fatty acids.They were discovered in the 1930s in the context of mammalian reproductive physiology; PGs were associated with the prostate gland, hence their name, and they stimulate uterine smooth muscle contraction.Determining PG chemical structures in the early 1960s and demonstrating that they mediate many human pathophysiological events in the 1970s stimulated intensive research over the following decades in universities, governments and the private sector.