Pituitary Gland

Pituitary Gland

A small organ at the base of the brain, the pituitary gland is a very powerful component of the endocrine system. Not much bigger than a pea, the pituitary gland secretes and produces many different hormones that not only regulate important biochemical processes, but also govern the behavior of other glands.

Occasionally, a pituitary gland tumor will grow that could alter the way the pituitary gland, in ways known as hypersecretion, hyposecretion, and tumor mass effects. These pituitary gland behaviors will be discussed shortly. In addition to disruptions caused by pituitary gland tumors, other conditions caused by a malfunctioning pituitary gland can also occur. One of these illnesses, acromegaly, will also be discussed in greater detail.

If you are looking for specific information, please visit our Pituitary Gland page. There you will find plentiful and detailed information about the conditions that can affect pituitary gland. Also available are PDF documents in both English and Spanish.

Hormones Produced by the Pituitary Gland

To get a better understanding of the reach of pituitary gland functions, and to better understand how these functions can be compromised by a pituitary gland tumor, it is worth taking a moment to take a closer look at the hormones produced by the pituitary gland and what each hormone does.

• Prolactin -- The primary functions of prolactin are to stimulate the production of breast milk following childbirth and to regulate sex hormone levels in both men and women.
• Growth hormone (GH) -- This hormone produced by the pituitary gland promotes growth in children. Too much growth hormone in children can create a condition known as acromegaly or gigantism. In adults, growth hormone helps to maintain muscle and bone mass as well regulate fat distribution.
• Adrenocorticotropin (ACTH) -- This hormone stimulates production of the “stress hormone”, cortisol, produced by the adrenal glands and is responsible for maintaining optimal blood pressure and glucose levels.
• Thyroid-stimulating hormone (TSH) -- This hormone governs vital processes and systems, such as energy, growth, metabolism and the nervous system by stimulating the thyroid gland. Variations in these levels could be the result of thyroid problems such as an overactive thyroid or an underactive thyroid. (You can learn more about each of those at our Thyroid Problems page.
• Antidiuretic hormone (ADH) -- Also known as vasopressin, this hormone’s function is to regulate the balance of water in the body. When levels of antidiuretic hormone are not where they should be, it can lead to conditions such as diabetes insipidus and syndrome of inappropriate ADH, both of which affect the kidneys.
• Luteinizing hormone (LH) -- This hormone regulates levels of testosterone by the testes and estrogen by the ovaries in men and women, respectively.
• Follicle-stimulating hormone (FSH) -- Working with luteinizing hormone, follicle-stimulating hormone promotes normal functioning of the ovaries and testes by regulating sperm production and ovulation in men and women, respectively.

With an understanding of systems affected by the pituitary gland, it is time to look at the affect that a pituitary gland tumor can have on the body.

Pituitary Gland Tumor: Secretory and Non-Secretory

A pituitary gland tumor will present itself as one of two types: secretory or non-secretory. A secretory pituitary gland tumor accelerates the production of hormones. Non-secretory tumors become problematic when their size begins to interfere with the normal functioning of the pituitary gland.

These two pituitary gland tumor types can cause three general types of problems.

• Hypersecretion -- Those with this pituitary gland condition face the increased production of certain hormones by the tumor. Illnesses extending from hypersecretion can include prolactinoma (the overproduction of prolactin) and acromegaly (the overproduction of growth hormone) and Cushing’s (the overproduction of ACTH).
• Hyposecretion -- As opposed to hypersecretion, hyposecretion is the result of too little hormone secretion. This can be caused by a non-secretory or secretory tumor that is interfering with normal pituitary gland processes, usually because of its large size.
• Tumor Mass Effects -- In some instances, a pituitary gland tumor may grow so large that it presses against other areas around the pituitary gland, leading to vision problems, headaches, and other hyposecretion-related problems.

To learn more about pituitary gland tumor characteristics and to gain more detailed information of the problems associated with a pituitary gland tumor, please visit our Pituitary Gland page. If you suspect you may have a pituitary gland tumor, you should consult a pituitary gland specialist.

Acromegaly

Although very rare, acromegaly is a visible illness related to the pituitary gland. As a hypersecretory condition caused by a pituitary gland tumor, acromegaly affects both children (known as gigantism) and adults and is characterized by the overproduction of growth hormone. Outward signs of acromegaly include abnormally large hands and feet, protruding forehead and jaw, thicker lips and teeth that are more widely spaced than normal. Course facial features are also common.

Our Pituitary Gland Resources Page contains more information about acromegaly, including diagnosis and treatment information.

Learn More About Pituitary Gland Disorders

If you or someone you know has been diagnosed with a pituitary gland tumor or other illness related to the pituitary gland, such as acromegaly, The Hormone Foundation aims to be your primary source for information online. Through the cooperation of endocrine specialists, educational programs, informative publications, and strategic partnerships, we hope to not only educate individuals about pituitary gland disorders and other endocrine system diseases, but also help them live better, healthier lives.

Editor:

Anne Klibanski, MD

March 2008

If you would like to learn more about The Hormone Foundation and the informational resources we offer, please Contact Us today.

Additional Information About the Endocrine System:

Underactive Thyroid

Osteoporosis Treatment

Polycystic Ovary Syndrome