| Abstract: | This study describes the binding of 3H]corticosterone and 3H] dexamethasone to soluble macromolecules in the pituitaries of adrenalectomized rats perfused at sacrifice to remove blood contamination. (1) Unlabeled dexamethasone competes only slightly for 3H] corticosterone binding when the steroids are added to cytosol as well as when the steroids are present from the time of disruption of the tissue. In the latter case, corticosterone is as good a competitor as dexamethasone for 3H]dexamethasone binding. (2) Gel permeation chrmatography with BioRad A-5M reveals the presence of a 3H] corticosterone-macromolecular complex with an elution volume comparable to transcortin as well as a very large hormone-binding complex eluting in the void volume of the column... |
