Table of ContentsView AllTable of ContentsAnatomyFunctionAssociated ConditionsTests
Table of ContentsView All
View All
Table of Contents
Anatomy
Function
Associated Conditions
Tests
About the size of a small pea, the pituitary gland, also known as “the master gland,” plays a crucial role in regulating hormone production from most of the other glands in the body. This being the case, it’s essential to numerous functions as well as overall health. Sitting in the brain between itshypothalamusregion andthe pineal glandwithin the sphenoid bone (located towards the front of the skull), this gland has two lobes: an anterior and a posterior lobe.
Ariel Skelley / Getty Images
Structure
The pea-sized pituitary gland is composed of both anterior and posterior lobes; in adults, the vertical diameter is approximately 8mm, with the horizontal circumference found to be 12 millimeters (mm).These are encased in a tough membrane (dura), and just beneath another such membrane, the sellar diaphragm, which has an opening to allow a structure called the infundibular stalk to exit the gland.
Each of these lobes has sub-parts and structures. Here’s a quick breakdown of these:
Location
The pituitary gland rests in a saddle-shaped depression in the middle of the sphenoid bone called the sella turcica. This butterfly-shaped, unpaired bone is located towards the front of the skull at about eye level. This places it just beneath theoptic chiasm(where theoptic nervescross), the hypothalamus, as well as the front portion of a ring of arteries called thecircle of Willis. It’s to the side of the cavernous sinus, a space that collects blood from central brain regions on its way back to the heart. To the front of the pituitary gland, you find a couple of other blood-collecting spaces—the anterior clinoid and anterior intercavernous sinuses.
Anatomical Variations
Several congenital variations occur with the pituitary gland. Among the most notable of these is that there is variation in size between men and women, with these being somewhat larger in the latter. Pregnancy also causes this gland to grow significantly in size.Similarly, the pituitary gland is larger during puberty and young adulthood, and it’s known to shrink after age 50.
Given its instrumental role in the body, the pituitary gland is highly influential on human development and functioning. Primarily, this is done through the synthesis of hormones. As mentioned above, the anterior lobe is the site of the majority of such activity and produces the following:
In addition, the posterior pituitary lobe synthesizes a couple of other hormones, which are:
A number of conditions and diseases can affect the pituitary gland: everything from infection or inflammation to the presence of tumors. A majority of the problems here are related to the latter case, and these are typically treated using eithergamma knife radiosurgery, which employs directed radiation to perform surgery, another type of radiotherapy called intensity-modulated radiation therapy (IMRT), or, in some cases, traditional surgery.
Pituitary Adenoma
Adenomas are tumors that grow on the pituitary gland. Almost always benign (noncancerous), these occur in about 20% of people and in many cases are asymptomatic.Their presence may be associated with other health conditions, such as high blood calcium level.
Due to their size,pituitary adenomaslead to under-activity of the gland or over-production of hormones (also known as hypopituitarism). Occasionally, these adenomas lead toheadachesor vision problems.
Hyperprolactinemia
This type of tumor causes the pituitary gland to produce the hormone, prolactin. Varying in size, with smaller ones called “microprolactinomas” and larger growths called “macroprolactinomas,” these can lead to discharges from the breasts in women, irregular menstruation, or even loss of menstrual function in women. In men, this condition can lead to impotence. Occasionally, these grow large enough to provoke symptoms.
Symptoms and Treatment of Hyperprolactinemia
Pituitary Apoplexy
This is a rare condition in which a pituitary adenoma enlarges in size and hemorrhages or infarcts, leading to obstruction of blood flow. In turn, this leads to sudden headaches, visual disturbances, reduced hormone production, and sometimes vomiting.
Pituitary Tumor Headaches
Cushing’s Disease
Occurring in cases where adenomas are causing hyperactivity of hormone production (ACTH)—Cushing’s syndromeleads to overactivity of adrenal glands, leading to overproduction of cortisol.
More common in women, this condition leads to progressive weight gain, depression, muscle weakness, and easy bruising of the skin. It can lead to impotence in men, and in women, it can cause irregular periods.
Hypopituitarism and Panhypopituitarism
Hypopituitarism is the situation in which the pituitary gland is not producing certain hormones, which can lead to panhypopituitarism, or an underproduction of all hormones from the pituitary gland. As with other conditions, this is the result of benign tumors impacting the anterior or peripheral lobes, or it can arise as an unintended side-effect of surgery. Occasionally, these arise due to infection or certain head injuries.
Symptoms include tiredness, irregular periods or even complete loss of menstrual function in women, impotence (in men), infertility, susceptibility to cold temperatures, constipation, dry skin, and low blood pressure.
If you complain of symptoms associated with pituitary dysfunction, your healthcare provider will first need to take a look at your medical history. This means that you’ll need to have any imaging or test results on hand for the consultation. If the situation calls for it, the pituitary gland can be assessed using a number of specialized approaches.
Insulin Tolerance Test
Used to test adrenal and pituitary gland function—and a common test for diabetes—this procedure involves administering insulin to induce hypoglycemia, or lower blood sugar. This allows the healthcare provider to assess how well this gland is able to produce necessary hormones.
Dexamethasone Suppression Test
Growth Hormone Stimulation Test (GHRH)
Also known as the arginine test, GHRH assesses the level of growth hormone (GH) production. This involves drawing blood and applying medicine to stimulate pituitary function and measuring these levels.
Growth Hormone Suppression Test
This tests for conditions involving overactive pituitary function, such as acromegaly. By suppressing growth hormone production using specific drugs, healthcare providers can assess for GH excess.
Magnetic Resonance Imaging (MRI)
After initial tests, practitioners may require imaging—often MRIs—to get a fuller sense of pituitary health and assess for the presence of any tumors.
8 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Ganapathy M, Tadi P.Anatomy, head and neck, pituitary gland.The Cleveland Clinic.Pituitary tumors & related pituitary disorders.Bronson R, Gaillard F.Pituitary gland: Radiology reference article. Radiopaedia.Botz B, Gaillard F.Empty sella: Radiology reference article.Sen D, Arora V.Duplication of the pituitary gland - plus syndrome.Indian Journal of Radiology and Imaging. 2016;26(1):126. doi:10.4103/0971-3026.178361American Brain Tumor Association.Pituitary tumors.Baruah M, Ranabir S.Pituitary apoplexy.Indian J Endocrinol Metab. 2011;15(7):188. doi:10.4103/2230-8210.84862University of California San Francisco.Growth hormone stimulation test.
8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Ganapathy M, Tadi P.Anatomy, head and neck, pituitary gland.The Cleveland Clinic.Pituitary tumors & related pituitary disorders.Bronson R, Gaillard F.Pituitary gland: Radiology reference article. Radiopaedia.Botz B, Gaillard F.Empty sella: Radiology reference article.Sen D, Arora V.Duplication of the pituitary gland - plus syndrome.Indian Journal of Radiology and Imaging. 2016;26(1):126. doi:10.4103/0971-3026.178361American Brain Tumor Association.Pituitary tumors.Baruah M, Ranabir S.Pituitary apoplexy.Indian J Endocrinol Metab. 2011;15(7):188. doi:10.4103/2230-8210.84862University of California San Francisco.Growth hormone stimulation test.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Ganapathy M, Tadi P.Anatomy, head and neck, pituitary gland.The Cleveland Clinic.Pituitary tumors & related pituitary disorders.Bronson R, Gaillard F.Pituitary gland: Radiology reference article. Radiopaedia.Botz B, Gaillard F.Empty sella: Radiology reference article.Sen D, Arora V.Duplication of the pituitary gland - plus syndrome.Indian Journal of Radiology and Imaging. 2016;26(1):126. doi:10.4103/0971-3026.178361American Brain Tumor Association.Pituitary tumors.Baruah M, Ranabir S.Pituitary apoplexy.Indian J Endocrinol Metab. 2011;15(7):188. doi:10.4103/2230-8210.84862University of California San Francisco.Growth hormone stimulation test.
Ganapathy M, Tadi P.Anatomy, head and neck, pituitary gland.
The Cleveland Clinic.Pituitary tumors & related pituitary disorders.
Bronson R, Gaillard F.Pituitary gland: Radiology reference article. Radiopaedia.
Botz B, Gaillard F.Empty sella: Radiology reference article.
Sen D, Arora V.Duplication of the pituitary gland - plus syndrome.Indian Journal of Radiology and Imaging. 2016;26(1):126. doi:10.4103/0971-3026.178361
American Brain Tumor Association.Pituitary tumors.
Baruah M, Ranabir S.Pituitary apoplexy.Indian J Endocrinol Metab. 2011;15(7):188. doi:10.4103/2230-8210.84862
University of California San Francisco.Growth hormone stimulation test.
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