Glucocorticoid receptors: relations between steroid binding and biological effects.

摘要: Abstract Steroid binding has been studied in cytoplasmic extracts of cultured rat hepatoma cells to investigate the mechanism enzyme induction by glucocorticoids. The affinity inducer steroids for specific receptors contained is directly related potency these as inducers tyrosine amino-transferase. ability anti-inducer compete with similar their inhibit induction. Furthermore, an can be predicted from its binding. These and other correlations allow distinction between a number molecules, includingplasma transcortin, which also bind glucocorticoid hormones. Further experiments were carried out determine whether allosteric model, proposed earlier, could explain differential effects inducer, suboptimal steroids. According interact either, or both, two conformational states receptors; uncomplexed are predominantly one (inactive) form inducers, but not anti-inducers, increases concentration (active) conformation. Consistent this idea, we find that less stable when they free, complexed anti-inducer, than bound inducer. kinetic studies accordance proposal associated changes receptor molecules. Specific characterized tissues found those tissue culture cells.