What is the hypothalamus and what does it do?

The hypothalamus is small but mighty in terms of its influence over your body. We explore its functions, the hormones it makes, hypothalamic disorders, and how you can keep your hypothalamus healthy.

• Functions of the hypothalamus
• Where is the hypothalamus located?
• Hormones produced by the hypothalamus 
• What can go wrong with the hypothalamus gland?
• Tips for a healthy hypothalamus

What is the hypothalamus and what does it do?
 

Like the thermostat in your home keeps the temperature stable, the hypothalamus keeps your body in a stable state (homeostasis) by responding to external and internal changes.

As a key part of the endocrine system, it constantly monitors and regulates parameters such as body temperature, fluid balance, and hormone levels.

If any abnormalities are detected, such as a spike in your blood sugar level, the hypothalamus secretes hormones — chemical messengers that act on other parts of the body to restore your internal balance.

Despite its small size (around the size of an almond), the hypothalamus is involved in many processes in your body.

Processes the hypothalamus helps regulate:

• Appetite and thirst
• Body temperature
• Childbirth
• Growth and development
• Heart rate and blood pressure
• Mood
• Sex drive
• Sleep cycle

Where is the hypothalamus located?
 

The hypothalamus is located at the base of the brain. It sits above the pituitary — another important endocrine gland. The two glands are directly connected by a stalk called the infundibulum.

The pituitary gland is often referred to as the master gland in the endocrine system, as it initiates action in many other endocrine glands. However, the hypothalamus may be more worthy of this title because many of the pituitary gland’s actions are directed by the hypothalamus.

What hormones are produced by the hypothalamus?
 

The hypothalamus makes two types of hormones:

1. Hormones that are transported to the pituitary, where they are stored and released directly into the bloodstream when required (oxytocin and anti-diuretic hormone).
2. Hormones that act on the pituitary, causing it to produce and release its own hormones, which stimulate other parts of the endocrine system.

Hormones made by the hypothalamus [1]:

Anti-diuretic hormone (ADH) — ADH helps regulate fluid balance and blood pressure. It combats dehydration and falling blood pressure by acting on the kidneys to help them manage the amount of water in your body. ADH also helps normalise blood pressure by acting as a powerful vasopressor, which promotes the constriction of the blood vessels. As a result, ADH is also known as vasopressin.

Corticotropin-releasing hormone (CRH) — CRH controls the release of adrenocorticotropic hormone (ACTH) by the pituitary gland. ACTH triggers the adrenal glands to produce cortisol, an important stress hormone.

Gonadotropin-releasing hormone (GnRH) — GnRH stimulates the release of luteinising hormone (LH) and follicle-stimulating hormone (FSH) by the pituitary gland. These act on the gonads (testes and ovaries) to stimulate the production of sperm or eggs in men and women, respectively. They also stimulate the production of sex hormones.

Growth hormone-releasing hormone (GHRH) and growth hormone-inhibiting hormone (GHIH) — GHRH stimulates the release of growth hormone by the pituitary gland and GHIH inhibits its release. Growth hormone controls the growth and repair of cells throughout our lives.

Oxytocin — this hormone initiates childbirth by stimulating contractions of the uterus. It also stimulates the release of milk during breastfeeding. Oxytocin is often referred to as the love hormone as it plays an important role in promoting mother/baby bonding, and other behaviours and emotions such as sexual arousal.

Prolactin-releasing hormone (PRH) and prolactin-inhibiting hormone (PIH) — PRH and PIH fine-tune the release of prolactin by the pituitary gland — PRH stimulates the secretion of prolactin while PIH inhibits prolactin secretion. Prolactin plays a vital role in initiating 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?
 

If your hypothalamus is damaged, it may not work the way it should. This is known as hypothalamic dysfunction.

Causes of hypothalamic dysfunction include:

• Brain injuries
• Brain surgery, radiation, or chemotherapy to treat brain tumours
• Congenital (present at birth) conditions
• Genetic disorders
• Infection and inflammation of the brain
• Malnutrition (e.g. caused by eating disorders such as anorexia and bulimia)
• Tumours in or around the hypothalamus

What are the symptoms of hypothalamic dysfunction?

Hypothalamus conditions can cause wide-ranging symptoms. These symptoms depend on the part of the hypothalamus and the hormones affected.

Symptoms of a problem with the hypothalamus include:

• Dehydration
• Delayed onset of puberty
• Failure to grow and thrive
• Fertility problems
• Frequent urination
• Increased or decreased appetite
• Insomnia
• Problems regulating body temperature
• Unexplained weight gain or loss
• Unusually high or low blood pressure

Hypothalamic disorders

Hypothalamic dysfunction can cause several disorders that affect many aspects of health and wellbeing such as appetite, sleep patterns, blood pressure, body temperature, and libido.

Hypothalamic disorders include:

• Diabetes insipidus — a rare condition where the hypothalamus doesn’t make and release enough ADH. This means the kidneys remove too much water from the body, causing frequent urination (polyuria).
• Prader-Willi syndrome — a rare genetic disorder where the hypothalamus doesn’t register that someone is full after eating. People with this syndrome have a constant urge to eat, increasing their risk of obesity.
• Hypopituitarism — a condition where the pituitary gland doesn’t make enough hormones. It’s usually caused by damage to the pituitary, but hypothalamic dysfunction can cause it too.

How are hypothalamic disorders diagnosed and treated?

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 (HRT), while surgery may be necessary to remove any physical pressure on the gland by a tumour.

It can be difficult to diagnose hypothalamic dysfunction as the glands of the endocrine system are so interconnected. The hypothalamus communicates directly with the pituitary gland, which in turn controls hormone production in other endocrine glands.

This can make it hard to distinguish hypothalamic dysfunction from pituitary dysfunction. And both can cause the same symptoms as disorders of other endocrine glands, such as thyroid or adrenal disorders.

For example, a thyroid condition might be caused by a problem with the thyroid hormones themselves, TSH released by the pituitary gland, or TRH produced by the hypothalamus.

How can I keep my hypothalamus healthy?
 

Some hypothalamic conditions are unavoidable, but there are some steps you can take to keep your hypothalamus healthy.

Tips for a healthy hypothalamus:

• Eat a balanced diet — studies in mice have shown that a diet high in fat and sugar can cause inflammation in the hypothalamus [2]. A well-balanced diet like the Mediterranean diet is a great option as it focuses on healthy fats and lean proteins.
• Exercise regularly — exercise can boost overall wellbeing and help you maintain a healthy weight.
• Get enough sleep — sleep deprivation is related to hypothalamus dysfunction and may increase the risk of neurological disease [3]. If you’re struggling to get your recommended 7-9 hours of sleep a night [4], tips for good-quality sleep include avoiding looking at your phone in the hour before you head off to bed.

What are the 10 endocrine glands?
 

In addition to the hypothalamus, the other major endocrine glands are:

• The pituitary gland
• The adrenals
• The ovaries and testes (gonads)
• The thyroid and parathyroid glands
• The pancreas
• The pineal
• The thymus

You can learn more about the endocrine system and other hormone-related topics in our Hormone Health Hub.

 

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References

1. MedlinePlus (2022) Hypothalamic dysfunction. Available at: https://medlineplus.gov/ency/article/001202.htm (Accessed 01 August 2024).
2. Kim, J. et al. (2014) Chronic sleep deprivation-induced proteome changes in astrocytes of the rat hypothalamus. Journal of Proteome Research, 13(9): 4047-4061. https://doi.org/10.1021/pr500431j
3. Gao, Y. et al. (2017) Dietary sugars, not lipids, drive hypothalamic inflammation. Molecular Biology, 6(8): 897-908. https://doi.org/10.1016/j.molmet.2017.06.008
4. NHS (no date) Sleep problems. Available at: https://www.nhs.uk/every-mind-matters/mental-health-issues/sleep/#:~:text=a%20great%20night.-,How%20many%20hours%20of%20sleep%20do%20I%20need%3F,naturally%20sleep%20more%20than%20others (Accessed 01 August 2024).