Modulation of the association between blood glucose homeostasis and social hierarchy among co-housed mice by diet and amygdala activities

Recent clinical studies suggest that individual psychosocial traits play a significant role in the onset and progression of diabetes. To examine whether glucose homeostasis depends on the social rank of individual mice, we analyzed the effects of dietary fat content on the hierarchy formed among co-housed mice and evaluated how perturbing rank by inhibiting amygdala neuronal activity influences glucose regulation. Social rank among four co-housed mice was assessed using the tube test. Switching to a high-fat diet altered blood glucose homeostasis, particularly by affecting rapid responses, and disrupted the established hierarchy, with the degree of disruption varying according to each mouse's rank. In contrast, chemogenetic inhibition of neuronal activities in the basolateral amygdala and surrounding area in the lowest-ranking mice modified both glucose homeostasis and its association with social rank. These findings provide mechanistic insight into the interaction between glucose regulation and psychosocial status.