5-trans Prostaglandin D2

PGD2 is one of the five primary enzymatic prostaglandins derived directly from PGH2. PGD2 is produced abundantly in the CSF by the lipocalin-type PGD synthase, and in the periphery by myeloid cells, including mast cells and basophils, by leukocyte-type PGD synthase.{8034,6647} 5-trans PGD2 is an isomer of PGD2 wherein the double bond between carbons 5 and 6 has been changed from cis (Z) to trans (E). The trans isomer of prostaglandin D2 (PGD2) occurs as an impurity between 2-5% in most commercial preparations of the bulk drug product. This compound was prepared primarily as an analytical standard for detection and quantitation of this impurity. From what can be inferred from the study of other trans isomers of F-type prostaglandins, the biological activity of 5-trans PGD2 is likely to be similar to that of the cis isomer. However, there are no specific published reports on the biological activity of 5-trans PGD2.