2-arachidonyl glycerol (2-AG) exhibits cannabinoid (CB) agonist activity at the CB1 receptor, is an important endogenous monoglyceride species, and is thus considered to be the natural ligand for the CB1 receptor. 2-AG can also be metabolized by cyclooxygenase-2 and specific prostaglandin H2 (PGH2) isomerases to form PG 2-glyceryl esters. Fluprostenol serinol amide (Flu-SA) is a stable analog of PGF2α 2-glyceryl ester that has much greater stability. The biological activity of Flu-SA has not yet been determined.