PURPOSE To investigate the effects of dexamethasone (DEX) on pigment epithelium-derived factor (PEDF) cDNA and secreted protein in human trabecular meshwork (TM). METHODS Anterior segment organ cultures were perfused with 0.1 microM DEX (OD) and vehicle (OS). Primary human TM cells (HTM) were treated with DEX under similar conditions. PEDF mRNA and secreted PEDF protein were quantitated by RT-PCR and Western blot. RESULTS PEDF mRNA and secreted PEDF protein levels were significantly higher in DEX over vehicle-treated cultures. In contrast, DEX decreased the activity of a 92-kDa gelatinolytic zymogen in organ culture effluents. CONCLUSION DEX action in the human TM might include a PEDF-mediating pathway.