Chronic stress from adolescence to adulthood increases adiposity and anxiety in rats with decreased expression of .

We previously identified , , as a novel adiposity gene, but subsequently found that its impact on adiposity may depend on environmental stress. To more thoroughly understand the connection between , adiposity, and stress, we exposed wild-type (WT) and knock-out (KO) rats to chronic stress then measured adiposity and behavioral outcomes. We found that KO rats displayed lower basal stress than WT rats under control conditions and exhibited metabolic and behavioral responses to chronic stress exposure. Specifically, stress-exposed KO rats gained more weight, consumed more food when socially isolated, and displayed more anxiety-like behaviors relative to control KO rats. Meanwhile, there were minimal differences between control and stressed WT rats. At study conclusion stress-exposed KO rats had increased corticosterone (CORT) relative to control KO rats with no differences between WT rats. In addition, KO rats, independent of prior stress exposure, had an increased CORT response to removal of their cage-mate (psychosocial stress), which was only seen in WT rats when exposed to chronic stress. Finally, we found differences in expression of the glucocorticoid receptor, , in the pituitary and colon between control and stress-exposed KO rats that were not present in WT rats. These data support that expression affects stress response, potentially via interactions with , with downstream effects on adiposity and behavior. Future work is necessary to more thoroughly understand the role of in the stress response.