Glucocorticoids Stimulate Ribonucleic Acid Degradation in Isolated Rat Thymic Lymphocytes in Vitro

TLDR: This data indicates that lymphocytes, which die in response to glucocorticoid, exhibit enhanced rates of cellular protein degradation, which encouraged this work to study the turnover of other lymphocyte cellular macromolecules, namely RNA, as regulated by adrenal steroids.

Abstract: Glucocorticoids are known to stimulate lymphoid cell death, but little information is available regarding the biochemical mechanisms of adrenal steroid-induced lymphocytolysis. Previous work from our laboratory indicates that lymphocytes, which die in response to glucocorticoid, exhibit enhanced rates of cellular protein degradation. These findings encouraged us to study the turnover of other lymphocyte cellular macromolecules, namely RNA, as regulated by adrenal steroids. Thymic lymphocytes were pulse labeled in vitro in Eagle's Minimum Essential Medium supplemented with 10 μCi/ml [3H] uridine. Precursor incorporation into RNA was effectively stopped by a chase/dilution (1:20) of cells into fresh medium supplemented with 10 mM of both unlabeled uridine and cytidine. Cells were incubated in this medium for up to 4 h at 37 C with or without dexamethasone (Dex), and the remaining RNA-associated radioactivity was measured either by acid precipitation or with a multiple automated sample harvester. Control cel...