THE MINERALOCORTICOID HORMONE-RECEPTOR AND ACTION IN THE EYE

Immunoblotting with a polyclonal antibody, directed against the minera locorticoid receptor protein purified from rat kidney in presence of t he receptor-specific ligand RU 26752, labeled a single 98-102 kDa band in soluble extracts from bovine retina and from cultured bovine retin al pigment epithelial cells, identical to the receptor in several othe r tissues from the rat. This antibody also immunoprecipitated the rece ptor-H-3-RU 26752 complex in bovine retinal extract. The growth of the isolated pigment epithelial cells was inhibited by RU 26752 and ZK915 87, two ligands specific to the mineralocorticoid receptor. Successive passages in culture led to the disappearance of immunoreactivity in W estern blots, concurrently with the refractoriness of the cells to gro wth inhibition by the two antagonists. On sections of the human eye, m ineralocorticoid receptor-specific immunofluorescence was observed in retinal cone cells, pigment epithelium, epithelium of ciliary body, ir is, cornea and lens. To our knowledge, this is the first ever demonstr ation of the mineralocorticoid receptor in ocular tissues. (C) 1996 Ac ademic Press, Inc.