Arachidonoyl ethanolamide was the first endogenous cannabinoid (CB) to be isolated and characterized as an agonist acting on the same receptors (CB1 and CB2) as THC. Since that time, a number of related endocannabinoids have been isolated, most notably 2-arachidonoyl glycerol . Lipoxygenases, especially rabbit reticulocyte and soybean 15-lipoxygenases, actively convert endocannabinoids to their 15(S)-hydroperoxy and hydroxy metabolites. 15(S)-HETE ethanolamide is less potent than AEA at the CB1 receptor (Ki of 600 versus 90 nM). 15(S)-HETE ethanolamide also inhibits fatty acid amide hydrolase.