What is the role of adrenocorticotropic hormone (ACTH) stimulation test in the diagnosis of hypopituitarism (panhypopituitarism)?

Updated: Jun 09, 2020
  • Author: Bernard Corenblum, MD, FRCPC; Chief Editor: Romesh Khardori, MD, PhD, FACP  more...
  • Print
Answer

The ACTH stimulation test, which evaluates the hypothalamic-pituitary-adrenal axis, is a superior tool in the diagnosis of adrenal insufficiency, but it does not generally separate pituitary from adrenal causation. This dynamic test measures serum cortisol levels before and after a 1- or 250-mcg dose of ACTH. The cortisol level should be greater than 500 pmol/L (may be  less in some assays) 30 minutes after ACTH administration in patients with normal adrenal function.

A low cortisol level that fails to rise after ACTH administration represents an abnormal cortisol response, a response seen in primary adrenal insufficiency. However, because of adrenal atrophy with chronic ACTH insufficiency, the cortisol response is often abnormal in patients with hypopituitarism. A poor response requires the serum ACTH, or other clinical clues, to separate pituitary from primary adrenal disease.

Other provocative tests for ACTH/cortisol function are the insulin-induced hypoglycemia test and the glucagon stimulation test. These may be needed within the acute stage of ACTH deficiency, such as following pituitary surgery.


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!