Cushing's disease. The adenoma in Cushing's disease causes the pituitary gland to produce an excessive amount of adrenocorticotropic hormone (ACTH), which, in turn, stimulates the adrenal glands to produce more cortisol than the body needs. Additionally, cortisol is produced in response to acute stress, triggering the well-known "fight or flight" response. In both situations, cortisol plays a vital role in regulating blood pressure, mobilizing energy reserves, and temporarily suppressing the immune system to deal with immediate challenges.