15-keto Prostaglandin E2-d4 (15-keto PGE2-d4) is intended for use as an internal standard for the quantification of 15-keto PGE2 by GC- or LC-MS. 15-keto PGE2 is a metabolite of PGE2 formed by 15-hydroxy PGDH.1,2 In vivo, 15-keto PGE2 is essentially inactive. 15-keto PGE2 has reduced affinity for the EP2 and EP4 receptors (Kis = 2,600 and 15,000 nM, respectively) compared to PGE2 (Kis = 53 and 7.3 nM for the EP2 and EP4 receptors, respectively).3
1.Hamberg, M., and Samuelsson, B.On the metabolism of prostaglandins E1 and E2 in manJ. Biol. Chem.246(22)6713-6721(1971) 2.Mak, O.T., Liu, Y., and Tai, H.H.Purification and characterization of NAD+-dependent 15-hydroxyprostaglandin dehydrogenase from porcine kidneyBiochim. Biophys. Acta1035(2)190-196(1990) 3.Nishigaki, N., Negishi, M., and Ichikawa, A.Two Gs-coupled prostaglandin E receptor subtypes, EP2 and EP4, differ in desensitization and sensitivity to the metabolic inactivation of the agonistMol. Pharmacol.50(4)1031-1037(1996)