Glucocorticoid receptor deficient thymic and peripheral T cells develop normally in adult mice

The involvement of glucocorticoid receptor (GR) signaling in T cell development is highly controversial, with several studies for and against. We have previously demonstrated that GR–/– mice, which usually die at birth because of impaired lung development, exhibit normal T cell development, at least in embryonic mice and in fetal thymus organ cultures. To directly investigate the role of GR signaling in adult T cell development, we analyzed the few GR–/– mice that occasionally survive birth, and irradiated mice reconstituted with GR–/– fetal liver precursors. All thymic and peripheral T cells, as well as other leukocyte lineages, developed and were maintained at normal levels. Anti‐CD3‐induced cell death of thymocytes in vitro, T cell repertoire heterogeneity and T cell proliferation in response to anti‐CD3 stimulation were normal in the absence of GR signaling. Finally, we show that metyrapone, an inhibitor of glucocorticoid synthesis (commonly used to demonstrate a role for glucocorticoids in T cell development), impaired thymocyte development regardless of GR genotype indicating that this reagent inhibits thymocyte development in a glucocorticoid‐independent fashion. These data demonstrate that GR signaling is not required for either normal T cell development or peripheral maintenance in embryonic or adult mice.