Factors affecting the distribution and stability of unoccupied 1,25-dihydroxyvitamin D3 receptors

Recently our laboratory reported that unoccupied 1,25(OH)2D3 receptors are found in the nuclei/chromatin fraction under low salt conditions in vitro (J. Biol. Chem. 255, 6799-6805, 1980). Additionally, various conditions exert differential effects on receptor solubilization and stability in vitro, potentially leading to confusion when these effects are not fully appreciated. In order to facilitate future studies, we have complied a review of these factors and their effects. The conditions discussed include dilution, ionic strength (KCl and molybdate), protease inhibitors (Trasylol, PMSF and TPCK), temperature, ligand, glycerol, dithiothreitol, and EDTA.