ABSTRACT
Separation of various forms of steroid hormone receptors on ion-exchange columns has been used widely to investigate the physical and functional parameters of these proteins. Early attempt to define more precisely steroid hormone receptor polymorphism simultaneously with receptor quantitation employed sedimentation velocity centrifugation on continuous sucrose density gradients (SDG). High-performance liquid chromatographic methods of analysis were initially investigated to overcome limitations of SDG centrifugation for the determination of receptor polymorphism. Steroid hormone receptor levels are usually determined by in vitro binding assays requiring the preparation of a crude cytosolic extract and its incubation with radiolabeled hormone analogs. The highly lipophilic steroid itself is retained to different extents on the AX300 and AX1000 columns. High-performance liquid chromatography techniques analyses of steroid receptors demonstrates the exhibit a far more complex profile, revealing details about the subunit organization in no way indicated by the SDG method which separates macromolecules essentially on the basis of their size, density, and the buoyancy of the solution.
