ACTH, adrenocorticotropic hormone, is a peptide hormone cleavage product of the POMC protein produced by the pituitary gland. ACTH plays an important role in stress and circadian rhythm signaling. Its primary action is on the adrenal cortex, where its binding induces the secretion of glucocorticoid steroid hormones. The peptide sequence for this hormone is highly evolutionarily conserved amongst mammals. Specifically, for mouse and rat, this sequence shares 100% identity.