Functions of the hypothalamus

Ever wondered what keeps your body from overheating or why you get thirsty? This little area set deep in your brain has the answers.

Buried deep in the brain, the hypothalamus is responsible for homeostasis - keeping the body in balance.

What is the hypothalamus and what does it do?

The hypothalamus is a small area of the brain which is located between the pituitary gland and the thalamus [1].

It’s part of the feedback loop that tells the body whether to produce more or less of a certain hormone to keep the body in balance (homeostasis).

The hypothalamus is responsible for the processes that regulate [2]:

Hormones produced in the hypothalamus

 

There are two types of hormones produced by the hypothalamus:

  1. Hormones that travel to the pituitary where they are released directly into the bloodstream (oxytocin and anti-diuretic hormone).
  2. Hormones that travel to the pituitary, where they control the production and release of further hormones which stimulate other parts of the endocrine system.

Hormones that are produced in the hypothalamus [3]:

  • Anti-diuretic hormone (ADH)- ADH (or vasopressin) controls the reabsorption of water into the blood from the kidneys.
  • Corticotropin-releasing hormone (CRH)- CRH controls the release of ACTH (see next chapter) by the pituitary gland to regulate the production of adrenal hormones.
  • Gonadotropin-releasing hormone (GnRH)- GnRH stimulates the release of luteinising hormone (LH) and follicle-stimulating hormone (FSH) by the pituitary gland. In men, these hormones cause the testicles to make more testosterone. In women, they cause the ovaries to make oestrogen and progesterone.
  • Growth hormone-releasing hormone (GHRH) and Growth hormone-inhibiting hormone (GHIH) - GHRH and GHIH stimulate the release or inhibition of growth hormone by the pituitary gland. Growth hormone controls the growth and repair of cells throughout our lives.
  • Oxytocin -Oxytocin is the hormone that stimulates the womb to contract during labour and the release of milk for breastfeeding.
  • Prolactin-releasing hormone (PRH)/ and prolactin inhibiting hormone (PIH)- PRH and PIH control the release or inhibition of prolactin by the pituitary gland. Prolactin stimulates the production of breast milk.
  • Thyrotropin-releasing hormone (TRH) -TRH stimulates the release of thyroid-stimulating hormone (TSH) by the pituitary gland. TSH controls the production of thyroid hormones which regulate metabolism.

What can go wrong with the hypothalamus gland?

Problems with the hypothalamus are often caused by trauma to the brain either through a head injury or surgery or by tumours that are in or close to the hypothalamus.

Other causes of hypothalamus disorders can be genetic or can be caused by malnutrition (including eating disorders such as anorexia), or infection and inflammation of the brain.

Hypothalamus dysfunction – what are the symptoms?

The hypothalamus has a wide role in the body, therefore a disorder of the hypothalamus can have many consequences that can make it difficult to diagnose.

The hypothalamus is part of a communication system with the pituitary gland which in turn controls hormone production in other hormone glands. Hypothalamus dysfunction can be difficult to distinguish from pituitary dysfunction, and both can cause the same symptoms as disorders of the other endocrine glands e.g. thyroid or adrenal disorders.

For example, a thyroid problem might be due to a problem with the thyroid hormones themselves, thyroid-stimulating hormone released from the pituitary gland, or thyrotropin releasing hormone produced by the hypothalamus.

Hypothalamus dysfunction can cause:

  • Failure to grow and thrive
  • Delayed puberty
  • Changes in appetite
  • Weight gain and fatigue
  • Unexplained weight loss
  • Fertility problems
  • Problems regulating body temperature

Diagnosis and treatment of hypothalamic disorders

Diagnosis of a hypothalamic disorder is made after a combination of clinical examinations, including eye tests and brain imaging to detect any lesions, as well as hormone blood tests to measure levels of circulating hormones.

Low levels of hormones can be treated with hormone replacement therapy, while surgery may be necessary to remove any physical pressure on the gland from a tumour.

Where next?

Learn more about other glands and their role in hormone health:

  1. The pituitary gland
  2. The adrenals
  3. The gonads
  4. The thyroid and parathyroid glands
  5. The pancreas, pineal and thymus
  6. Hormone blood test buying guide

References

  1. Yourhormones.info. 2022. Hypothalamus | You and Your Hormones from the Society for Endocrinology. [online] Available at: <https://www.yourhormones.info/glands/hypothalamus/> [Accessed 12 July 2022].
  2. Encyclopedia, M. and dysfunction, H., 2022. Hypothalamic dysfunction: MedlinePlus Medical Encyclopedia. [online] Medlineplus.gov. Available at: <https://medlineplus.gov/ency/article/001202.html> [Accessed 12 July 2022].
  3. Shahid Z, Asuka E, Singh G. Physiology, Hypothalamus. [Updated 2022 May 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available at: <https://www.ncbi.nlm.nih.gov/books/NBK535380/>

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