In 1936, Euler of Sweden identified in seminal fluid an active material that contracts smooth muscle; he named this lipid-soluble acid "prostaglandin." More than 20 years passed before the isolation in crystalline form of two prostaglandins, PGE1 and PGE1a, was accomplished. The elucidation of their chemical structures in 1962 by Bergstrom led to their biosynthesis in 1964. Few substances have generated more widespread interest in biologic circles than the prostaglandins.
The prostaglandins are derivatives of fatty acids and have been detected in almost every tissue including the fetal ductus. The E-type prostaglandins are powerful vasodilators of nearly all arterioles by direct relaxation of vascular smooth muscle.