13,14-dihydro-15-keto Prostaglandin E2 (13,14-dihydro-15-keto PGE2) is a metabolite of PGE2 and the primary PGE2 metabolite in plasma. It is formed from PGE2 via a 15-keto PGE2 intermediate by 15-oxo-PG Δ13 reductase. Unlike PGE2, 13,14-dihydro-15-keto PGE2 does not bind effectively to the PGE2 receptors EP2 and EP4 expressed in CHO cells (Kis = 12 and 57 μM, respectively) or induce adenylate cyclase activity in the same cells (EC50s = >18 and >38 μM, respectively). Levels of 13,14-dihydro-15-keto PGE2 are increased in the plasma of women in the third trimester of pregnancy and in women during and immediately after labor and delivery. Levels of 13,14-dihydro-15-keto PGE2 levels are decreased in tumor tissue compared to adjacent non-cancerous tissue isolated from patients with non-small cell lung cancer (NSCLC).
