tokens: In cytosolic fractions prepared from rat thymic lymphocytes , [ 3H ] -dexamethasone-21-mesylate labels a protein ( Mr approximately equal to 95 , 000 ) which was identified as the glucocorticoid receptor by the following criteria : ( a ) labeling of this moiety is inhibited by treatment with a 100-fold molar excess of glucocorticoids , such as dexamethasone and triamcinolone acetonide ; and ( b ) the covalently labeled Mr approximately equal to 95 , 000 protein is activated ( by heating at 20 degrees for 30 min ) to a form that binds to DNA-cellulose .