title: An effect of corticosteroids on thymocytes not mediated by macromolecule synthesis.
abstract: Rat thymocytes were incubated for 2 min at 37 degrees C and the cells then broken by osmotic shock in 1.5 mM MgCl2 and the nuclei harvested. Treatment with 50 nM dexamethasone for 2 min resulted in about one third of nuclei showing abnormalities in appearance, in shape and density. This was not prevented by prior incubation for 10 min with actinomycin D and cycloheximide, but was when nuclei were isolated in the presence of anions larger than F- and Cl-, including I-, Br-, SO = 4 and citrate identical to. Subsequent addition of Cl- ion, however, resulted in development of abnormalities in steroid-treated nuclei. It is concluded that the steroid induces a mechanism resulting in influx of chloride ion leading to nuclear edema, which is not mediated by processes involving synthesis of macromolecules.
mesh_terms: D000818:Animals; D000838:Anions; D002467:Cell Nucleus / Q000187:drug effects / Q000648:ultrastructure*; D003513:Cycloheximide / Q000494:pharmacology*; D003609:Dactinomycin / Q000494:pharmacology*; D003907:Dexamethasone / Q000494:pharmacology*; D005260:Female; D007930:Leucine / Q000378:metabolism; D014176:Protein Biosynthesis; D051381:Rats; D013950:Thymus Gland / Q000187:drug effects / Q000648:ultrastructure*
chemical_list: D000838:Anions; D003609:Dactinomycin; D003907:Dexamethasone; D003513:Cycloheximide; D007930:Leucine