Adrenocorticotropin, also known as ACTH, is a hormone produced in the pituitary gland that stimulates the production and release of cortisol from the adrenal glands. Synonyms for adrenocorticotropin include corticotropin, adrenocorticotropic hormone, and adrenotrophin. Corticotropin is commonly used in medical literature as a shorthand for adrenocorticotropin. Adrenotrophin is a less commonly used synonym for this hormone. ACTH plays an important role in regulating the body's response to stress and maintaining a healthy immune system. It is often used as a diagnostic tool for disorders related to the pituitary gland and adrenal glands.