IMMUNOCHEMICAL DETECTION OF THE MINERALOCORTICOID RECEPTOR IN RAT-BRAIN

The mineralocorticoid receptor (MCR) in the brain of adult male rats w as analyzed with the aid of an antiserum generated by immunizing rabbi ts with this protein purified biochemically from rat kidney. In Wester n blots, the antibody recognized a single band of protein of about 98 kD from all target tissues studied to date. The granular cells in the cerebellum appeared to be the richest region of the central nervous sy stem in the MCR analyzed by dot blots and by immunoperoxidase staining . High immunoreactivity was also observed in the dorsal and ventral hi ppocampus, as well as the anterior, mediobasal and posterior hypothala mus. In contrast, midbrain, septum and striatum were MCR-negative. The antibody macroaggregated and precipitated brain MCR labelled with H-3 -aldosterone but did not recognize H-3-RU 26752 bound nonspecifically to non-MCR proteins in whole brain cytosol. Thus, MCR function and exp ression in the adult rat brain need to be reassessed.