The influence of immobilization stress on cardiac protein synthesis. A possible regulatory role for glucocorticoids

High serum corticosterone levels and transient depletion of cytosolic glucocorticoid receptor binding capacity were observed in rat cardiac muscle following immobilization stress. To evaluate the effect of this treatment on the protein synthetic capacity, biologically active polyribosomes were used to direct the in vitro synthesis of polypeptides in the rabbit reticulocyte lysate. The results of these experiments indicate that the template activity of several messenger RNAs coding for major myofibrillar proteins was increased. This change in protein synthetic activity was not observed in adrenalectomized animals. Collectively, these results suggest that glucocorticoids are involved in the regulation of cardiac protein biosynthesis.