Adrenocorticotropic Hormone

What is Adrenocorticotropic Hormone?

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

Synthesis of Adreno Corticotropic hormone

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 its 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.

Functions of ACTH Hormone

  • 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.

Disorders of ACTH Hormone

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

Also Refer: Adrenal insufficiency

Hormones Levels and Risk Factors

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 joints 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 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 the cortisol levels, it results in the slow down 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 more 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 the 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 the low level 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 lifestyles 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 tumour.
  • Cushing’s disease.
  • Addison’s disease.
  • Bleeding in the adrenal glands.
  • Side-effect from radiation therapy.
  • Congenital adrenal hyperplasia.
  • A tumour outside the pituitary gland.
  • Other hormonal changes including low-level cortisol levels, high-level ACTH, Adrenal insufficiency, etc.

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

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

Frequently Asked Questions on ACTH Hormone

What is ACTH hormone deficiency?

ACTH hormone deficiency refers to decreased or low levels of ACTH hormone in the body, which is mainly caused by the reduced production of ACTH hormone or by pituitary gland malfunctions.

What is the function of adrenocorticotropic hormone?

Adrenocorticotropic hormone -ACTH is involved in the functioning of adrenal glands, regulation of the steroid hormone and production of stress hormones.

What does the ACTH hormone do?

Other functions of the ACTH hormone include:
  • Metabolism of glucose.
  • Catabolism of proteins.
  • Metabolism of immunosuppression.
  • Anabolic effects on muscle and bones.
  • Stimulation of spermatogenesis in men.

What happens when ACTH is high?

The higher levels of ACTH in the blood cells results in the following symptoms:
  1. Fatigue.
  2. Weight gain.
  3. Addison disease.
  4. Muscle weakness.
  5. Development of stretch marks on the abdomen, thighs, and on the breasts.

What are the symptoms of low ACTH?

The lower levels of ACTH in the blood cells results in the following symptoms:
  1. Diarrhoea.
  2. Weight loss.
  3. Mood swings.
  4. Hypoglycemia.
  5. Loss of appetite.

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