Fig. 1

Sex differences in HPA axis response to stress. Adult male versus female rodents have decreased HPA axis responses to acute stressors characterized by decreased paraventricular nucleus (PVN) neuronal activation and corticotropin-releasing hormone (CRH) gene expression, decreased pituitary expression of the proopiomelanocortin (POMC) precursor for adrenocorticotropin (ACTH), and decreased ACTH and corticosterone (CORT) responses to acute stressors. Males also have enhanced negative feedback (red arrow) resulting from their reduced corticosteroid-binding globulin (CBG) levels, their increased PVN glucocorticoid receptor (GR) gene expression, and their increased neuronal activation in limbic regions that inhibit the HPA axis. The sun symbol indicates neuronal activation