Characteristics of the corticosterone-receptor complex in rat liver cytosol.
Using a gel filtration on Sephadex G-150 in low ionic strength, it was possible to separate a corticosterone-binding protein in rat liver cytosol from corticosteroid-binding globulin after incubation of cytosol with [3H]corticosterone. The corticosterone-protein complex ("alpha-Complex") had a sedimentation coefficient of 8-9 S in low ionic strength. In high ionic strength, the alpha-Complex rapidly dissociated with a half-life of 15 h, compared to a half-life of 31 h for the hepatic dexamethasone-receptor complex under identical conditions (0 degrees C). The alpha-Compelx was saturable with an excess of unlabelled corticosterone of dexamethasone and was sensitive to heat and protease digestion. It is stressed that quantitation of the corticosterone-receptor complex must include separation of the receptor from corticosteroid-binding globulin as this protein binds corticosterone with high affinity and with a saturable amount of binding sites.
D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D003345:Corticosterone / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D003907:Dexamethasone / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000166:cytology*; D008297:Male; D011485:Protein Binding; D011506:Proteins / Q000302:isolation & purification / Q000378:metabolism; D051381:Rats; D011956:Receptors, Cell Surface
D011506:Proteins; D011956:Receptors, Cell Surface; D003907:Dexamethasone; D003345:Corticosterone