LY171883 is a selective, potent, orally active antagonist of the leukotriene D4 receptor. Dissociation constants (KB) for LY171883 on guinea pig ileum and parenchyma are 0.07 and 0.34 μM, respectively. LY171883 is an inhibitor of phosphodiesterase obtained from human polymorphonuclear leukocytes (IC50 of 22.6 μM) and various guinea pig tissues (IC50s range from 6.9-209 μM). At a concentration of 50-100 μM, LY171883 binds to the PPARγ nuclear receptor, inducing adipogenesis in cultured NIH3T3 fibroblasts.