Adrenocorticotropic Hormone

Table of Contents

• What is Adrenocorticotropic Hormone?
• Synthesis of Adrenocorticotropic Hormone
• Functions of ACTH Hormone
• Disorders of ACTH Hormone
• Hormones Levels and Risk Factors

Adrenocorticotropic Hormone (ACTH) is a hormone produced in the anterior pituitary gland of the brain. This hormone is involved in regulating the steroid hormone and cortisol levels, released from the adrenal gland.

ACTH is also known as arginine vasopressin, adrenocorticotrophin, serum adrenocorticotropic hormone or corticotropin.

Adrenocorticotropic hormone is the most vital hormone required for the functioning of adrenal glands, which stimulates the production of stress hormones from the cortex, called cortisol.

Also Refer: Endocrine Glands

Corticotrophin-releasing hormone of the hypothalamus stimulates the pituitary gland to secrete adrenocorticotropic hormone (ACTH). The secreted adrenocorticotropic hormone travels to the adrenal glands through the bloodstream. Cortisol from the adrenal glands supplies back to the hypothalamus to shut down the cycle.

ACTH is produced in the basophilic cells of the anterior pituitary gland, where it is released and carried through the bloodstream and transported around the body. Like cortisol, levels of the adrenocorticotropic hormone are usually high in the morning when we wake up and drop their level throughout the day – reaching their lowest level during sleep. This natural and internal process is called a circadian or diurnal rhythm.

The secretion of ACTH is controlled by three regions of the body:

1. Hypothalamus.
2. Pituitary gland.
3. Adrenal glands.

• Bone resorption.
• Catabolism of proteins.
• Primarily dehydroepiandrosterone.
• Anabolic effects on muscle and bones.
• For stimulation of spermatogenesis in men.
• Metabolism of glucose, androgens, lipolysis, hyperglycemia and immunosuppression.

• Pituitary tumours.
• Cushing’s disease.
• Congenital adrenal hyperplasia.
• Adrenal insufficiency including Addison’s disease.

Also Refer: Adrenal insufficiency

The normal level of ACTH hormones varies with the age and sex of an individual. According to medical reports, the normal level of ACTH hormones is 6.0 to 76 pg/ml or 1.3 to 16.7 pmol/L.

Low level of Adrenocorticotropic Hormone

If the ACTH level of an individual is low compared to the normal value, then the person is suffering from Cushing syndrome.

The changes in the levels of ACTH are detected by the adrenal gland receptors.

The causes for the lower secretion of the adrenocorticotropic hormone can be due to hypopituitarism, side effects from pituitary gland surgery and other Cushing’s diseases.

The symptoms of low levels of adrenocorticotropic hormone include:

• Vomiting.
• Diarrhoea.
• Weight loss.
• Mood swings.
• Hypoglycemia.
• Loss of appetite.
• Chronic fatigue.
• Abdominal pain.
• Muscle weakness.
• Hyperpigmentation
• Scars and skin folds.
• Low blood pressure.
• Muscle and joint pain.
• Irregular menstruation in women.

High level of Adrenocorticotropic Hormone

If the ACTH level of an individual is high compared to the range value, then the person is suffering from Addison’s disease.

The higher levels of ACTH are mainly caused by the stimulation of adrenal gland receptors for more production of cortisol and therefore, resulting in the rise of cortisol levels in the blood cells.

As there is a rise in cortisol levels, it results in a slowdown in the release of corticotrophin-releasing hormone from the hypothalamus and ACTH from the pituitary gland. As a result, the ACTH levels start to fall. This is called a negative feedback loop.

Other external factors responsible for stimulating ACTH production include both physical and psychological stress.

As discussed above, the symptoms of high levels of adrenocorticotropic hormone include:

• Acne.
• Fatigue.
• Weight gain.
• Muscle weakness.
• Increased body hair.
• Skin that bruises quickly.
• A buildup of fat in the shoulders.
• Pink or purple stretch marks on the abdomen, thighs and on breasts.

Also Refer: Hormones and Hormonal Disorders

What is the ACTH test used for?

An ACTH test is mainly used to measure the levels of both ADH and cortisol in the blood cells. This test is used to diagnose or detect diseases, which are associated with high-level or low levels of cortisol in the body.

Disorders Of ACTH

The disorders of the ACTH are mainly caused by the regulation of ACTH production in the body. These may be increased in the level of ACTH production or decreased. Based on age and lifestyle changes, certain disorders occur in an individual.

Listed below are a few factors which are mainly responsible for the increase or decrease in adrenocorticotropic hormonal levels, which include:

• Adrenal tumours.
• Cushing’s disease.
• Addison’s disease.
• Bleeding in the adrenal glands.
• The side-effect of radiation therapy.
• Congenital adrenal hyperplasia.
• A tumour outside the pituitary gland.
• Other hormonal changes include low-level cortisol levels, high-level ACTH, Adrenal insufficiency, etc.

This article concludes with an introduction to the Adrenocorticotropic hormone (ACTH), its level of production and its functions.

To know more about the Adrenocorticotropic hormone (ACTH), other related topics and important questions, keep visiting our website at BYJU’S Biology