• Mifepristone is a specific glucocorticoid receptor antagonist that has been shown to lower intraocular pressure modestly when applied topically to rabbit eyes. We evaluated the ability of mife-pristone to block specific in vitro glucocorticoid receptor binding of the labeled agonist triamcinolone acetonide in cytosol isolated from rabbit iris-ciliary body tissue. A 500-fold molar excess of nonradioactive mifepristone completely blocked specific binding of triamcinolone acetonide to glucocorticoid receptors in the iris-ciliary body cytosol. Additionally, specific binding was blocked in a dose-dependent fashion over a range of 0.005-fold to 500-fold molar excess of mifepristone. Mifepristone's effect on intraocular pressure may be due to its ability to antagonize glucocorticoid receptor-mediated effects in ocular tissues.
Munden PM, Schmidt TJ. Mifepristone Blocks Specific Glucocorticoid Receptor Binding in Rabbit Iris—Ciliary Body. Arch Ophthalmol. 1992;110(5):703-705. doi:10.1001/archopht.1992.01080170125039