What is ACTH?
ACTH is produced in the pituitary gland and released into the blood. The hormone stimulates cells in the adrenal gland to produce glucocorticosteroids (cortisone).
Hormones from the hypothalamus and adrenal gland regulate the level of ACTH concentration. It also fluctuates during the day: in the morning there is a lot of ACTH in the blood, in the evening less.
During stress such as mental or physical strain, cold, illness or injury, ACTH is released in greater quantities. If enough cortisone is available, the formation of ACTH is throttled. An ACTH deficiency in turn leads to a lack of cortisone.
When is ACTH determined in the blood?
The doctor determines the ACTH concentration when he suspects that the patient’s adrenal cortices are no longer producing enough cortisone. He does this to check whether the deficiency is due to a lack of stimulation from the pituitary gland.
Even if the patient has too much cortisone in the blood (Cushing’s disease) and the cause is still unclear, the ACTH concentration must be determined.
ACTH – normal values
|
Normal values |
8 – 10 o’clock |
8 – 10 pm |
|
Adults, children |
10 – 60 pg/ml |
3 – 30 pg/ml |
Values may differ slightly from other reference values.
Most often, ACTH levels are determined in the evening.
When is the ACTH value decreased?
- Dysfunction of the pituitary gland
- Cortisone-producing tumor of the adrenal cortex
- Enlargement of the adrenal cortex with increased cortisone production
When is the ACTH level elevated?
Elevated ACTH levels are found:
- in hypofunction of the adrenal cortex (Addison’s disease)
- occasionally in lung cancer
- occasionally in pancreatic cancer
- in a tumor of the pituitary gland (central Cushing’s syndrome)
What to do if ACTH is elevated or decreased?
If the ACTH level is increased or decreased, the concentration of cortisone in the blood must also be determined. Furthermore, a so-called dexamethasone test and a CRH stimulation test follow. In these tests, hormones are administered and the response of ACTH production is measured. In this way, the cause of the altered concentration of ACTH in the blood can be found. If necessary, further examinations such as X-rays and CT scans of the head follow.