Characterization of glucocorticoid receptors bound with corticosterone

The physico-chemical properties of glucocorticoid receptors bound with tritiated corticosterone were compared to those of the triamcinolone acetonide glucocorticoid receptor complex. The goal was to determine whether the natural agonist forms complexes similar to those generated by the synthetic agonist. Structure was probed using three techniques; diethylaminoethyl-cellulose (DEAE) chromatography, vertical tube rotor sucrose gradient ultracentrifugation (SGU) and high performance liquid chromatography (HPLC). These techniques are all fast enough to allow analysis of the labile corticosterone receptor complexes. Results showed that complexes generated by both classes of ligands were similar. They eluted from DEAE cellulose and HPLC columns at similar positions and sedimented similarly in sucrose gradients. This was true for both the untransformed and transformed species. It is concluded that natural and synthetic glucocorticoid agonists interact with glucocorticoid receptors to form indistinguishable complexes. Thus synthetic agonists are appropriate probes of events which take place with natural glucocorticoids.