title: Inactivation of glucocorticoid receptors in cell-free preparations of rat liver.
abstract: We have examined the rates of inactivation of glucocorticoid receptors in cell-free preparations from several rat tissues. The t1/2 of inactivation of the glucocorticoid-binding ability of thymus, heart, and kidney cytosols (37,000 X g supernatants) ranges from 2 to 4 hr at 0 degrees, whereas that of liver is much slower (15 to 25 hr). The rate of inactivation of the glucocorticoid-binding capacity of soluble preparations from liver varies roughly according to the g force at which they have been centrifuged. The 100,000 X g supernatant. The ability of the particulate enzyme to inactivate glucocorticoid receptors at 0 degrees is not affected by protease inhibitors but is inhibited by fluoride and molybdate. The rapid inactivation of unbound glucocorticoid receptors that occurs in a high-speed (100,000 X g) supernatant preparation from rat liver at 25 degrees can be completely inhibited by molybdate. These observations suggest that the inactivation of glucocorticoid receptors observed in cell-free liver preparations in vitro is due to a nonproteolytic enzymatic function.
mesh_terms: D000818:Animals; D002474:Cell-Free System; D002498:Centrifugation; D003600:Cytosol / Q000378:metabolism; D004798:Enzymes / Q000494:pharmacology; D066298:In Vitro Techniques; D007668:Kidney / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000378:metabolism; D009928:Organ Specificity; D009994:Osmolar Concentration; D011480:Protease Inhibitors; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000187:drug effects / Q000378:metabolism*; D011987:Receptors, Steroid / Q000378:metabolism*; D013950:Thymus Gland / Q000378:metabolism
chemical_list: D004798:Enzymes; D011480:Protease Inhibitors; D011965:Receptors, Glucocorticoid; D011987:Receptors, Steroid