Glucocorticoid mechanism of action: monoclonal antibodies as experimental tools.

In order to provide a further insight into glucocorticoid receptor (GR)-mediated action of glucocorticoid hormones, we produced ten monoclonal antibodies against rat GR. In studies combining physicochemical separation methods with antibody methodology, we established that the molybdate-stabilised GR contains one steroid-binding monomer. Using a monoclonal anti-GR antibody-based immunoaffinity chromatographic procedure, we purified two non-ligand-binding proteins, with molecular weights of 80,000 and 90,000, present in the molybdate-stabilised GR complex. These proteins are not recognised by monoclonal antibodies directed against GR. The possible relation of these two proteins to heat shock proteins remains to be established. Immunohistochemical studies of GR in the central nervous system of the rat provided new information on the distribution of GR, particularly in the hypothalamus. Studies of intracellular receptor localisation in rat brain after endocrine manipulations gave results in support of the classical concept of translocation of GR from cytoplasm to cell nucleus. Studies with a cell culture system also supported the existence of GR in the cytoplasm as well as in the cell nucleus.