2-Arachidonoyl glycerol (2-AG; Item No. 62160) has been isolated from porcine brain, and has been characterized as the natural endocannabinoid ligand for the CB1 receptor.{4614,5306} 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.{11045} 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.{10555}