ACTH and Cortisol
The Level of ACTH and cortisol in the body are directly related. When the level of ACTH
goes up the level of cortisol goes up. When the level of ACTH goes down so does the
cortisol level.
The body possesses an elaborate feedback system for controlling cortisol secretion and
regulating the amount of cortisol in the bloodstream. The pituitary gland, a small gland
at the base of the brain, makes and secretes a hormone known as adrenocorticotrophin, or
ACTH. Secretion of ACTH signals the adrenal glands to increase cortisol production and
secretion. The pituitary, in turn, receives signals from the hypothalamus of the brain in
the form of the hormone CRH, or corticotropin-releasing hormone, which signals the
pituitary to release ACTH. Almost immediately after a stressful event, the levels of the
regulatory hormones ACTH and CRH increase, causing an immediate rise in cortisol levels.
When cortisol is present in adequate (or excess) amounts, a negative feedback system
operates on the pituitary gland and hypothalamus which alerts these areas to reduce the
output of ACTH and CRH, respectively, in order to reduce cortisol secretion when adequate
levels are present. |
