Corneal endothelial cells synthesize prostaglandin E2 (PGE2), and this synthesis is necessary for the maintenance of the normal polygonal shape of these cells. A series of experiments was done to examine the receptor-effector mechanism responsible for PGE2-mediated effects on cultured rabbit corneal endothelium. When challenged with exogenous PGE2, endothelial cells synthesized cyclic adenosine monophosphate (AMP) in a dose-dependent manner, and this synthesis was not antagonized by AH6809. The synthetic agonist 11-deoxy-PGE1, but not sulprostone, stimulated increased cyclic AMP synthesis. The pharmacologic profile of the endothelial PGE2 receptor is therefore consistent with that of an EP2 receptor linked to activation of adenylate cyclase. The prostaglandin agonists were also tested for their ability to prevent cellular elongation in response to indomethacin. The PGE2, 11-deoxy-PGE1, and 16,16-dimethyl PGE1 prevented elongation, but sulprostone and PGF2 alpha did not. The authors conclude that rabbit corneal endothelium in culture expresses a specific PG receptor of the EP2 subtype which is coupled to cyclic AMP synthesis and is involved in the regulation of cell shape.