Corticotropin: definition, functions and associated diseases

The human body works in the same way as a production line. To get a final result (in this case a physical or bodily response), a series of previous reactions must first be given. For example, when we perceive the symptoms of stress, a series of chain reactions have already taken place inside our body.

One of the agents that make this chain reaction possible is corticotropin. A complex and multifunctional hormone that we will be talking about throughout this article.

What is corticotropin?

Also known as ACTH, adrenocorticotrope or corticotropin, this hormone secreted by the pituitary gland falls under the category of tropical polypeptide hormones and although it is mainly related to stress processes and reactions, it is also used as a medicine. and a diagnostic factor for a large number of organic conditions.

Discovered in 1933 by the American biochemist Evelyn M. Anderson, this hormone has been the subject of countless research, due to the large number of functions and effects it has on the body, as well as for its form of complex action.

At present, we know that corticotropin is one of the main agents involved in the functioning of the hypothalamic-pituitary-adrenal axis and that its production has traditionally been associated with a biological response to stress.

In addition, this hormone plays a key role in the regulation and release of other hormones called steroids. By stimulating the activity of the adrenal and adrenal glands, ACTH promotes the release of hormones such as adrenaline and norepinephrine.

However, as we have seen previously, the main function of the corticotropic hormone is to increase the levels of cortisol and corticosterone in the blood. It occurs in response to stress and its main effect on the body is related to the metabolism of fats, carbohydrates, proteins and blood pressure.

Likewise, the role of corticotropin is closely related to the circadian rhythms of our body. She herself works differently throughout the day, generating higher ACTH peaks in the morning, especially upon awakening, and decreasing throughout the day. This is known as the daytime rhythm of adrenocorticotropin.

As for the possible therapeutic effects of adrenocorticotropin, it is often used in the treatment of inflammation. Made as an anti-inflammatory, it is given to inflammatory conditions such as rheumatoid arthritis, lupus erythematosus, and ulcerative colitis.

Production and regulation

The synthesis of corticotropin is carried out in the anterior lobe of the pituitary gland, also known as the adenohypophysis. However, the regulation and control of its release is linked to three interconnected regions of our body: the hypothalamus, pituitary and adrenal glands. This structure is known as the hypothalamic-pituitary-adrenal axis.

When ACTH levels in the blood are lower than usual, the small group of cells in the hypothalamus release a hormone known as corticotropin-releasing hormone, which stimulates the activity of the pituitary gland. to secrete more adrenocorticotropin into the blood.

However, when the adrenal glands detect an excess of this hormone, which causes the blood cortisol levels to increase, there is automatically a decrease in the corticotropin releasing hormone, so that the amount of adrenocorticotropin in the torrent begins to decrease. This is called a negative feedback loop.

Pathologies associated with ACTH

Due to its role in a large number of activities and functions of our body, abnormal corticotropin levels can cause a large number of diseases and clinical conditions.

These ACTH-related illnesses vary widely depending on whether they are caused by increased levels of this hormone in the blood or, conversely, if its cause is adrenocorticotropin deficiency.

1. Excess ACTH in the blood

The effects of excess adrenocorticotropic hormone are a direct consequence of increased blood cortisol levels. While this increase in corticosteroid hormones is not expected to pose a health hazard, abnormally high levels are usually associated with the following conditions:

  • Cushing’s disease: This condition is caused by a cancerous tumor or adenoma located in the pituitary gland and is usually linked to abnormal levels of ACTH.
  • tumor formations located outside the pituitary gland known as the ectopic tumor of the adrenocorticotropic hormone.
  • Addison’s disease: Characterized by abnormally low cortisol levels but excessively high ACTH levels.
  • Congenital adrenal hyperplasia: A genetic disease characterized by inadequate production of cortisol and / or aldosterone.

2. ACTH deficiency

Conversely, the person may have adrenocorticotropic hormone deficiency also due to the development of tumor formations or as a side effect of radiation therapy or pituitary surgery.

In this case, the main conditions associated with this deficit are:

  • adrenal insufficiency: The adrenal glands stop producing ACTH properly, resulting in a decrease in adrenal androgens.
  • Cushing’s disease: In addition to an excess of ACTH, it can also be linked to an ACTH deficit.
  • clinical conditions of the pituitary gland as hypopituitarism.

Although these are the main clinical illnesses associated with adrenocorticotropin, there is a large list of other conditions in which this hormone plays a special role. Among them we find:

  • Small cell carcinoma
  • Nelson syndrome
  • West syndrome or infantile spasms
  • Post-orgasmic disease syndrome

Bibliographical references:

  • Sponsors A, Stevenaert A, Foidart JM, Hennen G and Frankenne F (1991). Secretion of placental and pituitary growth hormones during pregnancy in acromegasic women. J Clin Endocrinol Metab 71: 725.

  • Guyton-Hall (2001). Treatise on medical physiology, 10th ed., McGraw-Hill-Inter-American.

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