Pituitary Gland: Anatomy, Hormones, Function and Related Conditions
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: what is the pituitary gland?
The pituitary gland is a small endocrine gland below the hypothalamus that coordinates hormone signals involved in growth, metabolism, reproduction, stress response, lactation and water balance. It communicates with the hypothalamus through the pituitary stalk and with other glands through hormones released into the bloodstream. [1]
Core idea | Plain-language meaning |
Location | Base of the brain, below the hypothalamus and behind the bridge of the nose. |
Size | About the size of a pea or kidney bean; less than 1 gram. |
Main parts | Anterior lobe and posterior lobe. |
Main connection | Pituitary stalk linking it with the hypothalamus. |
Hormone roles | Growth, metabolism, reproduction, stress response, lactation, water and sodium balance, and childbirth. |
Common evaluation | Blood tests; CT or MRI may also be used. |
What the research says
Non-functioning pituitary adenomas are associated with higher mortality. A systematic review and meta-analysis that included 11 studies found that people with non-functioning pituitary adenoma had a higher risk of death than the general population (standardized mortality ratio 1.57, 95% CI 1.20–1.99), based on the five studies that reported mortality ratios, with about 130,000 person-years of follow-up. The ratio was higher in those diagnosed at age 40 or younger (3.19), and the excess mortality was seen regardless of pituitary function (Bioletto et al., J Endocrinol Invest, 2024). [2]
Water-balance problems after pituitary surgery are usually temporary in adenomas. A systematic review and meta-analysis of 51 studies on central diabetes insipidus (vasopressin deficiency) after transsphenoidal surgery found transient cases in 16% and permanent cases in 2% of people with pituitary adenomas. Permanent vasopressin deficiency was much more common after surgery for craniopharyngioma (30%) and Rathke's cleft cyst (14%) (Fountas et al., Eur J Endocrinol, 2024). [3]
Head injury can affect the pituitary. A review reported a pooled prevalence of anterior hypopituitarism of 27.5% after traumatic brain injury from a meta-analysis, with growth hormone deficiency the most common deficiency. Reported rates vary with the assays used, severity of head trauma and timing of evaluation (Fernandez-Rodriguez et al., Endocrinol Metab Clin North Am, 2015). [4]
Where is the pituitary gland located?
The pituitary gland is at the base of the brain, below the hypothalamus and behind the bridge of the nose. It sits in an indentation in the sphenoid bone called the sella turcica, a saddle-like compartment that surrounds and protects the gland. [1]
The pituitary connects with the hypothalamus through the pituitary stalk, also called the infundibulum. The stalk contains blood vessels and nerves that allow the two structures to communicate. [1]
How big is the pituitary gland?
A healthy pituitary gland weighs less than 1 gram and is about the size of a pea or kidney bean. The anterior lobe is larger than the posterior lobe and accounts for about 80% of the gland's total weight. [1]
A small size does not mean a small role. The gland releases hormones that influence several body systems and other endocrine glands.
What are the parts of the pituitary gland?
The pituitary has two main sections: the anterior pituitary, or front lobe, and the posterior pituitary, or back lobe. The two lobes have different tissue types and different connections with the hypothalamus. [1]
The anterior pituitary is the larger lobe. It consists of hormone-secreting epithelial cells and connects with the hypothalamus through blood vessels. The posterior pituitary consists of unmyelinated secretory neurons and connects with the hypothalamus through a nerve tract. It stores and releases hormones made by the hypothalamus. [1]
Lobe | Structure and role |
Anterior pituitary | Larger lobe; hormone-secreting epithelial cells; communicates through blood vessels. |
Posterior pituitary | Secretory neurons; communicates through a nerve tract; stores and releases hypothalamic hormones. |
Which hormones does the pituitary gland make or release?
The anterior pituitary makes and releases six hormones: ACTH, FSH, growth hormone, LH, prolactin and TSH. [1]
The posterior pituitary stores and releases antidiuretic hormone (ADH, also called vasopressin) and oxytocin. The hypothalamus makes these hormones and directs the posterior lobe when to store and release them. [1]
Anterior pituitary hormones
Hormone | Main role |
ACTH | Helps the body respond to stress by stimulating the adrenal glands to produce cortisol; cortisol also affects metabolism, blood pressure, blood glucose and inflammation. |
FSH | Stimulates sperm production in males; in females, stimulates ovarian estrogen production and plays a role in egg development. |
Growth hormone | Promotes growth in children; in adults helps maintain healthy muscles and bones, affects fat distribution and influences metabolism. |
LH | Stimulates ovulation in people with ovaries and testosterone production in people with testicles. |
Prolactin | Stimulates breast-milk production after giving birth and can affect fertility and sexual function in adults. |
TSH | Stimulates the thyroid to produce hormones that manage metabolism, energy levels and the nervous system. |
Posterior pituitary hormones
Hormone | Main role |
ADH or vasopressin | Regulates water balance and sodium levels. |
Oxytocin | Helps labor progress, causes breast milk to flow, influences bonding between parent and baby and plays a role in moving sperm. |
What does the pituitary gland control?
The pituitary gland's hormones help coordinate growth, metabolism, reproduction, response to stress or trauma, lactation, water and sodium balance, and labor and childbirth. [1]
A helpful comparison is a thermostat. Just as a thermostat monitors temperature and signals heating or cooling changes, the pituitary monitors body functions and sends hormone signals to organs and glands. The settings the body needs can vary with factors such as age and sex. The pituitary especially affects the thyroid, reproductive organs (including ovaries and testes) and adrenal glands. [1]
How do the hypothalamus and pituitary work together?
The hypothalamus and pituitary form a closely connected complex that acts as a central command center for vital body functions. The hypothalamus sends messages to the autonomic nervous system and directs the pituitary to produce and release hormones affecting other parts of the body. [1]
Through the pituitary stalk, the hypothalamus communicates with the anterior lobe using hormones and with the posterior lobe through nerve impulses. The hypothalamus also makes ADH and oxytocin and tells the posterior pituitary when to store and release them. [1]
Hypothalamic hormones that communicate with or stimulate the pituitary include CRH, dopamine, GnRH, GHRH, somatostatin and TRH. Damage to either the hypothalamus or pituitary can affect the hormonal function of the other. [1]
Can a person live without a pituitary gland?
A person can live without a pituitary gland if medication replaces the pituitary hormones that are missing. Pituitary hormones are important for several body functions, and an untreated lack of all pituitary hormones is life-threatening. [1]
This information is not a reason to start, stop or change any medicine. Hormone replacement and monitoring must be managed by a qualified healthcare professional.
What conditions are related to the pituitary gland?
The four main categories are pituitary adenomas, hypopituitarism, hyperpituitarism and empty sella syndrome. [1]
Pituitary adenomas
A pituitary adenoma is a benign, or noncancerous, growth on the pituitary gland. Adenomas make up 10% to 15% of tumors that develop within the skull. They are usually slow-growing. [1]
If an adenoma becomes large, it can press on nearby structures, compress the optic nerve and cause vision disturbances such as loss of peripheral vision. In rare cases, a large adenoma can bleed internally. [1]
A functioning (secreting) adenoma releases excess pituitary hormones. A non-functioning adenoma does not release hormones. Prolactinoma, which releases excess prolactin, is the most common functioning adenoma. [1]
Tumors that grow too large or release hormones require treatment, usually involving surgery, while prolactinomas are typically treated with medication. Treatment decisions are individualized and require clinical assessment.
Hypopituitarism
Hypopituitarism means the pituitary gland makes too little of one, multiple or all of its hormones. Most cases involve one hormone deficiency. A deficiency of all or nearly all pituitary hormones is called panhypopituitarism, which can happen after pituitary surgery or brain radiation, among other causes. [1]
Hypopituitarism is most often caused by damage to the pituitary gland or hypothalamus. Named hormone-deficiency conditions include growth hormone deficiency, central diabetes insipidus, central hypogonadism, central adrenal insufficiency and central hypothyroidism. Treatment involves replacing lacking hormones and monitoring hormone levels through blood tests. [1]
Hyperpituitarism
Hyperpituitarism means the pituitary gland makes too much of one or more hormones. It is often caused by a functioning or secreting pituitary adenoma. [1]
Excess hormone condition | Description |
Acromegaly | Too much growth hormone in adulthood; can enlarge hands, feet and/or organs and cause metabolic issues. |
Gigantism | Too much growth hormone during childhood or adolescence; causes rapid growth and very tall height. |
Cushing's disease | Too much ACTH causes the adrenal glands to make too much cortisol; can cause rapid weight gain in certain areas and high blood sugar. |
Hyperprolactinemia | Too much prolactin; can cause infertility and milky nipple discharge. |
Empty sella syndrome
Empty sella syndrome is rare. It occurs when the pituitary becomes flattened or shrinks because of issues with the sella turcica. [1]
Empty sella is a radiographic diagnosis and is often found accidentally on imaging. It does not always translate into a true medical condition. In some cases it may be associated with hormone imbalances, frequent headaches and vision changes. If pituitary hormone levels are within normal ranges, it is not a cause for concern.
What are symptoms of pituitary gland problems?
Large pituitary adenomas can press on or damage nearby tissues. Possible symptoms include vision problems such as loss of peripheral vision, headaches and hormone imbalances caused by too much or too little hormone. [1]
Hormone imbalances can cause different symptoms depending on the affected hormone, including lack of growth or excess growth in children, infertility in males or females, irregular periods, unexplained weight gain or loss, and depression and/or anxiety. [1]
Symptoms are not specific to pituitary disease. New or persistent symptoms should be discussed with a healthcare professional, who can use blood tests to assess whether hormone issues or another condition may be involved.
How are pituitary gland problems diagnosed?
Because the pituitary releases hormones directly into the bloodstream, healthcare professionals often use blood tests to measure pituitary hormone levels. [1]
When hormone levels are irregular, a CT scan or MRI may be ordered to evaluate the gland. A dedicated pituitary MRI is typically used to see the pituitary gland and stalk more clearly. [1]
Evaluation tool | What it may help assess |
Blood tests | Pituitary hormone levels. |
CT scan | The pituitary gland and surrounding structures. |
MRI scan | The gland and stalk, with dedicated pituitary MRI used for clearer views. |
Which healthcare professionals treat pituitary conditions?
Endocrinologists typically treat pituitary gland issues. An endocrinologist specializes in hormones and endocrine conditions, including diagnosis, treatment planning, management and prescription of medication. [1]
If a pituitary issue such as an adenoma affects brain structures or requires surgery, a neurosurgeon may also be involved. [1]
How can you protect pituitary health?
The best way to protect the pituitary is to protect the head, because head injuries and traumatic brain injuries can damage the pituitary and cause too little or too much hormone release. [1]
Prevention measures include wearing a seat belt whenever driving or riding in a vehicle, practicing safe driving and wearing a helmet for activities such as bicycling, motorcycling and contact sports. Fall prevention may include strength and balance exercises, removing obstacles and tripping hazards, using a walking aid when needed and making sure vision is clear. Living and play areas should be made safe for children. After a traumatic brain injury, a healthcare professional may monitor pituitary function. [1]
Prevention topic | Example |
Vehicle safety | Wear a seat belt and practice safe driving. |
Protective equipment | Wear a helmet for biking, motorcycling and contact sports. |
Fall prevention | Use strength and balance exercises, remove hazards and use walking aids when appropriate. |
Child safety | Make living and play areas safe for children. |
Post-injury monitoring | Pituitary function may be monitored after a traumatic brain injury. |
When should you contact a healthcare professional?
Discuss new or persistent symptoms such as headaches, vision changes, loss of peripheral vision, unexplained changes in weight, irregular periods, infertility, unusual growth patterns, depression or anxiety with a healthcare professional. These symptoms can have many causes and do not establish a pituitary diagnosis.
Seek evaluation after a traumatic brain injury, because pituitary function may need monitoring. A sudden severe headache, sudden vision change or other rapidly worsening neurological symptom is an emergency: call 911 or go to the emergency room, as it can signal bleeding into the pituitary (pituitary apoplexy) or a stroke. This article cannot determine the urgency of an individual situation.
Conclusion: a small gland with broad influence
The pituitary gland is a pea-sized endocrine gland at the base of the brain. Through its two lobes and its connection with the hypothalamus, it helps coordinate hormones involved in growth, metabolism, reproduction, stress response, lactation and water balance.
Pituitary conditions can involve too little or too much hormone, a benign adenoma or a change in the sella turcica. Symptoms may include headaches, vision changes and hormone-related effects, but they are not specific enough to diagnose a condition on their own. Blood tests and pituitary imaging can help healthcare professionals evaluate suspected hormone or structural problems. Use this guide to prepare questions for an endocrinologist or another qualified clinician.
Frequently Asked Questions
What is the pituitary gland?
A small endocrine gland at the base of the brain that makes and releases hormones and signals other endocrine glands.
Where is the pituitary gland located?
Below the hypothalamus, behind the bridge of the nose, in a bony compartment called the sella turcica.
How big is the pituitary gland?
A healthy pituitary weighs less than 1 gram and is about the size of a pea or kidney bean.
What are the two parts of the pituitary gland?
The anterior pituitary is the front lobe, and the posterior pituitary is the back lobe.
Which hormones does the anterior pituitary make?
ACTH, FSH, growth hormone, LH, prolactin and TSH.
Which hormones does the posterior pituitary release?
It stores and releases ADH (vasopressin) and oxytocin, which the hypothalamus makes.
What does ACTH do?
ACTH stimulates the adrenal glands to produce cortisol and contributes to the body's response to stress.
What do FSH and LH do?
FSH supports sperm production or ovarian estrogen production and egg development. LH stimulates ovulation in people with ovaries and testosterone production in people with testicles.
What does growth hormone do?
It promotes growth in children and helps maintain healthy muscles and bones, affects fat distribution and influences metabolism in adults.
What do prolactin and TSH do?
Prolactin stimulates breast-milk production after giving birth and can affect fertility and sexual function. TSH stimulates the thyroid to make hormones that manage metabolism, energy and the nervous system.
What does ADH or vasopressin do?
It regulates water balance and sodium levels.
What is a pituitary adenoma?
A benign, noncancerous growth on the pituitary gland. Large or hormone-secreting adenomas can cause problems.
What is hypopituitarism?
A lack of one, multiple or all of the hormones made by the pituitary gland.
What is hyperpituitarism?
Production of too much of one or more pituitary hormones, often related to a functioning pituitary adenoma.
What is empty sella syndrome?
A rare condition in which the pituitary becomes flattened or shrinks because of issues with the sella turcica. It may be found incidentally on imaging.
What symptoms can pituitary problems cause?
Possible symptoms include headaches, peripheral-vision loss, hormone imbalances, unusual growth patterns, infertility, irregular periods, unexplained weight changes, depression or anxiety.
How are pituitary problems diagnosed?
Healthcare professionals commonly use blood tests to measure pituitary hormone levels. CT or MRI, often a dedicated pituitary MRI, may also be used.
Which healthcare professional treats pituitary problems?
Endocrinologists typically treat them. A neurosurgeon may also be involved when an adenoma affects brain structures or requires surgery.
Can a person live without a pituitary gland?
Yes, if missing hormones are replaced with medication, but an untreated lack of all pituitary hormones is life-threatening.
How can I protect my pituitary gland?
Protect your head with seat belts and helmets, practice safe driving, reduce fall hazards and make children's play areas safe. After a traumatic brain injury, pituitary function may need monitoring.
When should I seek medical advice?
Discuss new or persistent symptoms, vision changes, hormone-related concerns or a recent traumatic brain injury with a healthcare professional. A sudden severe headache, sudden vision change or rapidly worsening neurological symptoms need emergency care: call 911 or go to the emergency room.
Related reading
Understanding the hypothalamus: the brain's homeostasis center
Understanding the endocrine system: functions, organs and health
Pituitary tumors and adenomas: types, symptoms and treatment guide
Prolactinoma: complete guide to the most common pituitary tumor
Panhypopituitarism: understanding the total lack of pituitary hormones
Hyperpituitarism: a comprehensive guide to overactive pituitary disorders
Growth hormone deficiency (GHD): what it is, why it happens and how it's treated
Acromegaly: complete guide to symptoms, causes, diagnosis and treatment
Cushing syndrome: what high cortisol does to your body and how it is treated
Central diabetes insipidus (CDI): the rare thirst condition caused by a hormone shortage
Pituitary apoplexy: symptoms, causes and emergency management
References
Cleveland Clinic. Pituitary Gland: What It Is, Function & Anatomy. Cleveland Clinic. Updated April 4, 2022. https://my.clevelandclinic.org/health/body/21459-pituitary-gland
Bioletto F, Sibilla M, Gasco V, et al. Excess mortality in patients with non-functioning pituitary adenoma: a systematic review and meta-analysis. J Endocrinol Invest. 2024;47(9):2143-2155. PMID 38503992. https://doi.org/10.1007/s40618-024-02356-9
Fountas A, Coulden A, Fernández-García S, et al. Central diabetes insipidus (vasopressin deficiency) after surgery for pituitary tumours: a systematic review and meta-analysis. Eur J Endocrinol. 2024;191(1):S1-S13. PMID 38996052. https://doi.org/10.1093/ejendo/lvae084
Fernandez-Rodriguez E, Bernabeu I, Castro AI, et al. Hypopituitarism after traumatic brain injury. Endocrinol Metab Clin North Am. 2015;44(1):151-159. PMID 25732651. https://doi.org/10.1016/j.ecl.2014.10.012
Disclaimer
This article is for general educational purposes and is not a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified healthcare professional with any questions about a medical condition or treatment.
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