What is plasma ACTH & Cortisol Response?

Question

What is plasma ACTH & Cortisol Response?

Answer 1

It's a test for adrenal and/or pituitary or hypothalamic  insufficiency.

Answer 2

ACTH is the adrenocorticotropic hormone found in the blood.

ACTH is made in the pituitary gland in response to the release of another hormone, called corticotropin-releasing hormone (CRH), by the hypothalamus. In turn, the adrenal glands then make a hormone called cortisol, which helps your body manage stress. Cortisol is needed for life, so its levels in the blood are closely controlled. When cortisol levels rise, ACTH levels normally fall. When cortisol levels fall, ACTH levels normally rise.

Both ACTH and cortisol levels change throughout the day. ACTH is normally highest in the early morning (between 6 a.m. and 8 a.m.) and lowest in the evening (between 6 p.m. and 11 p.m.). ACTH levels may be tested in the morning or evening if your doctor thinks that they are abnormal. Cortisol levels are often measured at the same time as ACTH.

Because ACTH is released in bursts, its levels in the blood can vary from minute to minute. Usually when people take the ACTH test, it is a timed test and is done in about 15 minute intervals for about 1 hour.  It is referred to as plasma ACTH because the blood is usually spun down in a hematology lab and the test is ran on plasma.