Hydrolysis of 11-palmitoyloxy-delta 9-tetrahydrocannabinol to 11-hydroxy-delta 9-tetrahydrocannabinol by cholesterol esterase and a lipase.

11-Palmitoyloxy-delta 9-tetrahydrocannabinol (11-palm-delta 9-THC) has been identified in the rat in our laboratory as a long-retained metabolite of delta 9-tetrahydrocannabinol (delta 9-THC), the active component of marihuana (Leighty, 1973). Although it is not known as yet if 11-palm-delta 9-THC is itself psychoactive it could be hydrolyzed to active 11-hydroxy-delta 9-tetrahydrocannabinol (11-OH-delta 9-THC). Our in vitro studies show that cholesterol esterase and a lipase can hydrolyze 11-palm-delta 9-THC to 11-OH-delta 9-THC.