C57BL/6 (B6) and the congenic strains B10.A and Rag2–/–, AND TCR-transgenic mice (21 (link)), β-actin-FLPe (22 (link)), FoxN1-Cre-transgenic mice (23 (link)), and β-actin-Cre mice were obtained from Jackson Laboratory. Lck-Cre–transgenic mice were obtained from Taconic. Nr3c1 (GR) exon 3 conditionally targeted mice were described (13 (link)). A conditional Cyp11b1 allele with loxp sites flanking exons 3-5 was generated by recombineering (24 (link)) (Supplemental Fig. 1A) and Cyp11b1-floxed mice were generated using C57BL/6 ES cells. The Neo cassette was removed by crossing floxed mice with β-actin-FLPe transgenic mice. All mice used in this study were backcrossed for at least 6 generations onto B6. Primer sequences used for genotyping are provided in Supplemental Table 1.