The hypothalamic-pituitary-adrenal (HPA) axis is the core neuroendocrine stress system coordinating hypothalamic corticotropin-releasing signaling, pituitary ACTH secretion, and adrenal glucocorticoid output.[1][2] It plays a central role in homeostasis, stress adaptation, immune modulation, and mood-related circuitry.
HPA-axis dysregulation is repeatedly referenced from pages involving stress biology, depression, anxiety, and neurodegeneration.[1:1][2:1] It is particularly useful as a mechanism-level target for links from amygdala, BNST, and serotonergic circuit pages.