11β-Prostaglandin F2αethanolamide (11β-PGF2α-EA), posited as the hepatic metabolite derived from PGD2-EA during COX-2 metabolism of AEA—an endogenous cannabinoid present in brain, liver, and various mammalian tissues—is synthesized directly from AEA via COX-2 and specific prostaglandin synthase, leading to ethanolamide versions of classical prostaglandins. Additionally, PGD2-EA formation occurs in activated RAW 264.7 cells upon AEA treatment.