title: Steroid production in the thymus: implications for thymocyte selection.
abstract: The mouse thymus was assessed for its ability to produce steroids. Cultured thymic non-T cells produced soluble pregnenolone and deoxycorticosterone, and immunohistochemistry demonstrated steroidogenic enzymes in radioresistant thymic epithelial cells but not in thymocytes. Inhibition of thymic corticosterone production or blockade of the glucocorticoid receptor with RU-486 resulted in enhanced TCR-mediated, antigen-specific deletion of immature thymocytes. These data indicate that locally produced glucocorticoids, because of their antagonism of TCR-mediated signaling for death, may be a key element of antigen-specific thymocyte selection.
authors.affiliation: Laboratory of Immune Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: M S
authors.initials: MS
authors.lastname: Vacchio
authors.forename: V
authors.initials: V
authors.lastname: Papadopoulos
authors.forename: J D
authors.initials: JD
authors.lastname: Ashwell
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D002478:Cells, Cultured; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000096:biosynthesis; D003345:Corticosterone / Q000096:biosynthesis* / Q000494:pharmacology; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D003900:Desoxycorticosterone / Q000096:biosynthesis*; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism / Q000528:radiation effects; D005333:Fetus; D008212:Lymphocyte Depletion; D008797:Metyrapone / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D015735:Mifepristone / Q000494:pharmacology; D009924:Organ Culture Techniques; D011284:Pregnenolone / Q000096:biosynthesis*; D011948:Receptors, Antigen, T-Cell / Q000187:drug effects / Q000502:physiology; D011965:Receptors, Glucocorticoid / Q000187:drug effects / Q000502:physiology*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*
chemical_list: D011948:Receptors, Antigen, T-Cell; D011965:Receptors, Glucocorticoid; D015735:Mifepristone; D003900:Desoxycorticosterone; D011284:Pregnenolone; D003577:Cytochrome P-450 Enzyme System; D002786:Cholesterol Side-Chain Cleavage Enzyme; D003345:Corticosterone; D008797:Metyrapone