Fig. 1.

Experimental timeline

After arrival at the experimental room (Day −28), all mice were housed singly for four weeks. At day 1, experimental wild type (WT; GR^+/+) and GR^dim (GR^dim/dim) homozygous mice were weighed and assigned to either the single-housed control (SHC) or the chronic subordinate colony housing (CSC) group. In order to induce chronic psychosocial stress, a group of four CSC mice (two WT and two GR^dim mice per cage) was housed together with a dominant male CD-1 mouse for 19 consecutive days. To avoid habituation, CSC mice were exposed to a novel dominant male CD-1 mouse on days 8 and 15. All animals were tested for anxiety-related behavior in the open-field/novel object (OF/NO) test on day 15 and for depressive-like/coping behavior in the forced swim test (FST) on day 19 of CSC, before being euthanized in the morning of day 20. Afterwards, the severity of bite wounds was assessed for bite score analysis. Trunk blood was collected for the assessment of plasma corticosterone (CORT) and adrenocorticotropic hormone (ACTH). The adrenal glands, the pituitary as well as the spleen were removed and weight. Adrenal glands were frozen for the assessment of the adrenal lipid content by Oil Rred-O staining. The pituitary was frozen for quantitative polymerase chain reaction (qPCR) analysis of proopiomelanocortin (POMC). Moreover, splenocytes were isolated for an in vitro glucocorticoid (GC) sensitivity assay. Experimental timeline was partly created with BioRender.com.