PGE2-d4-1-glyceryl ester contains four deuterium atoms at the 2, 2′, 3, and 3′ positions. It is intended for use as an internal standard for the quantification of PGE2-1-glyceryl ester by GC- or LC-mass spectrometry. 2-Arachidonoyl glycerol (2-AG) has been isolated from porcine brain, and has been characterized as the natural endocannabinoid ligand for the CB1 receptor.1,2 Incubation of 2-AG with COX-2 and specific prostaglandin H2 (PGH2) isomerases in cell cultures and isolated enzyme preparations results in prostaglandin glycerol ester formation.3 The biosynthesis of PGH, PGD, PGE, PGF, and TXA-2-glyceryl ester compounds have all been documented. The 2-glyceryl ester moiety equilibrates rapidly (within minutes) with the more stable 1-glyceryl ester, producing a 10:90 2:1-glyceryl ester mixture in typical aqueous media. While the stability and metabolism of these prostaglandin products has been investigated, little is known about their intrinsic biological activity.4WARNING This product is not for human or veterinary use.