Cushing's Syndrome: Corticotropin-Releasing Hormone

Topic Overview

The corticotropin-releasing hormone (CRH) stimulation test helps find out if a pituitary tumor may be causing Cushing's syndrome. It is sometimes done with an inferior petrosal sinus sampling (IPSS) test.

In these tests, a small tube called a catheter is used. A health professional uses it to collect samples from blood vessels coming from the pituitary gland near the brain and also from a vein in your arm. First you will get a shot of CRH. Then samples of your blood near your pituitary gland and from your arm are taken.

If these blood samples show high levels of adrenocorticotropic hormone (ACTH) and cortisol, it usually means that the pituitary gland has a tumor.

If blood levels of ACTH and cortisol do not rise, your doctor may then look for an adrenal tumor or a cancerous tumor elsewhere in your body.