The investigations should test the hypothesis that, in some cases, glucocorticoid hormones may act in the cytoplasm at the translational level, as well as via the well-established pathway of nuclear processing of the cytosol receptor complex. The availability of alternate pathways of steroid action might explain in part the variety of effects of the same steroid treatment in different target tissues. Studies will concentrate on the in vitro protein synthesizing systems of microsomes or their purified subfractions to investigate the effects of added free corticoid or of the isolated corticoid-receptor complex on protein synthesis and/or degradation. The possible role of RNase -RNase inhibitor activities in the protein synthesis or degradation will also be studied. Contrasting cell types (anabolic v. catabolic target tissues) will be used to try to relate the biochemical results with the known biological effects of glucocorticoid hormones. The systems used are liver, an "anabolic" target organ, and thymus, a "catabolic" target organ for glucocorticoids, as well as the mouse Lymphosarcoma P1798, Steroid-sensitive and Steroid-resistant Strains.