Plasma adrenocorticotropic hormone measurement is used to investigate the causes of hypercortisolemia and hypocortisolemia.
In response to a stimulus such as stress, the hypothalamus secretes the corticotropin-releasing hormone. This hormone stimulates the secretion of adrenocorticotropic hormone (ACTH) from the anterior pituitary lobe. ACTH in turn stimulates the adrenal cortex to release the glucocorticoid hormone cortisol. As blood cortisol levels rise, the pituitary gland is activated to reduce ACTH production through a negative feedback mechanism.
There are daily fluctuations in ACTH levels, with peak levels between 6 and 8 in the morning and lower levels between 6 and 11 in the evening. Minimum levels are about half to two-thirds of maximum levels. ACTH levels are used in combination with cortisol levels to assess adrenal cortex function.
Possible Interpretations of Pathological Values
- Increase: Addison's disease, ACTH ectopic production syndrome, pituitary adenoma, primary adrenal insufficiency, stress
- Decrease: Cushing's syndrome, hypopituitarism, primary adrenal cortical hyperactivity (tumors), secondary hypoadrenalism. Medications: Amphetamines, calcium gluconate, corticosteroids, estrogens, ethanol, lithium carbonate, spironolactone.
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. The correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.