Meet Your Body's Master Gland, The Pituitary

By: 
Laurence Katznelson, MD and Nicholas A. Tritos, MD, DS, FACP, FACE

The pituitary gland. You’ve likely heard of it, but what does it actually do?

As with many of the endocrine system’s collection of glands, the pituitary toils away consistently and inconspicuously with little recognition of its considerable contribution to a person’s well-being.....that is, until its performance goes awry. That’s when you learn just how important the pituitary is to your body’s overall function. In fact, it is often referred to as the body’s “master gland.”

So what is the function of this tiny structure? Why is it so important? And how would you know if it’s not operating properly? Here we provide an overview of this fascinating organ.

What is the pituitary gland?

Found at the base of the brain behind the bridge of the nose, the pituitary gland is often referred to as the endocrine system’s control center. This is because it controls many glands, among them the thyroid glands, the ovaries, the testicles (testes) and the adrenal glands.

Remarkably, this regulating gland is no larger than the size of an average pencil eraser. It produces many hormones that travel throughout the body, directing certain processes or stimulating other glands to produce hormones. Among them are prolactin, which stimulates breast development and milk production after childbirth and also affects sex hormone levels and fertility; growth hormone, which stimulates growth in children and is important for maintaining muscle and bone mass in adults; vasopressin, which regulates the amount of water excreted by the kidneys; ACTH (adrenocorticotrophin hormone), which stimulates the production of the “stress hormone” cortisol, which is produced by the adrenal glands; and TSH (thyroid stimulating hormone), which influences the thyroid gland to produce more hormones when a too-low level of thyroid hormone is detected. TSH decreases when satisfactory thyroid hormone bloods levels have been reached.

The pituitary gland is connected to, and controlled in large part by, the hypothalamus, a region of the brain that lies just above the pituitary. By detecting the levels of hormones produced by glands under the pituitary’s control, the hypothalamus or the pituitary can determine how much stimulation the glands need.

What are the symptoms of a pituitary disorder?

The pituitary gland can malfunction in several ways, as a result of a tumor or when there is over- or under-production of one or more hormones, which can happen at the same time.

How do you know if you have a pituitary problem? If you can answer yes to one or more of the following questions, you may want to consider scheduling an appointment with an endocrinologist to determine an appropriate course of action.

For Adults

Have you experienced change in vision, either loss of side (peripheral) vision or blurred vision? Are you experiencing menstrual irregularities? Are you experiencing sexual dysfunction? Are you experiencing an enlargement of the fingers, face or forehead? Do you bruise easily (without injury)? Do your muscles feel weak?

For Children

Are they growing at a normal rate? Are they showing signs of puberty too early? Girls before age 7? Boys before age 8? Are they lacking signs of puberty, including girls over age 13 or boys over age 14? Are they drinking excessive amounts of water (more than 2 quarts per day)?

For Menarchal Girls

Do they have a milky discharge from their breasts? Have they missed more than one period?

Pituitary Tumors

The most common type of pituitary disorder is a non-cancerous tumor (an adenoma). If you feel that you may have symptoms which could be caused by a pituitary tumor, you should discuss these symptoms with your physician. A detailed history and physical examination will then be done to determine whether measurement of specific pituitary hormones is necessary, as well as formal visual field testing. If findings are suggestive that a tumor may be present, a pituitary magnetic resonance imaging (MRI) examination will be ordered.

If you have been diagnosed with an adenoma, here is some information to help guide you. First, pituitary tumors are not a common cause of medical problems. They represent only about 10 percent of all tumors in the head. They are not “brain tumors,” since the pituitary is located just below the main portion of the brain. Pituitary tumors may sometimes cause headaches, but this is actually quite rare. They do not cause loss of thinking function, movement or sensation. However, if untreated, pituitary tumors may lead to loss of vision as well as symptoms arising as a consequence of pituitary hormone deficiency or excess. Working with an endocrinologist, a specialist in endocrine disorders, as part of your healthcare team is a vital component in maintaining an optimal lifestyle while living with pituitary abnormalities. With proper care, many people live with pituitary problems and lead normal, healthy, happy lives.

In addition to pituitary adenomas, there are many other, less-common conditions that can affect the pituitary gland, including other tumors, cysts and inflammation. These can also cause pituitary underactivity or lead to vision loss.

Once diagnosed, your treatment will be determined based on how the tumor was found. If the tumor was discovered as part of a routine MRI examination, then further testing will be necessary, which will be more extensive if the tumor exceeds a certain size or appears on the MRI image to press upon the visual pathway. If the tumor was found because of pressure symptoms or loss of pituitary function, detailed hormonal testing as well as visual evaluation is necessary. If the tumor was found because of over-secretion of pituitary hormones, the rest of the pituitary hormones will need to be tested.

What are the treatment options for pituitary tumors?

Treatment is based upon the behavior of the pituitary gland. If it is overproducing prolactin, then it will be treated, in most cases, with an oral medication (pill) which can reduce the over-secretion of this hormone and often shrink the tumor if one is present. If the tumor is secreting excess growth hormone (causing a condition called acromegaly or gigantism), or ACTH, which can cause Cushing’s disease, then the gland will be treated in most cases with surgery aimed at removing the tumor while sparing the normal gland.

Generally, pituitary tumors are removed by an operation called a transsphenoidal adenomectomy, performed while the patient is under general anesthesia. The pituitary gland is reached by a surgical incision on the inside of the nose or lip; the surgeon then proceeds through the sinus cavity to reach the tumor. The surgeon generally uses an endoscope or an operating microscope to provide magnification and allow an optimal view of the tumor during surgery. A small incision is often made in the skin of the abdomen to remove a small amount of fat tissue, which is used to pack the wound after the pituitary tumor is removed.

In the event that surgery becomes necessary, it is extremely important that surgery be performed by an experienced pituitary neurosurgeon, as surgical results are dependent upon the skill and experience of the surgeon. Your endocrinologist should discuss with you the surgical team in your area which is best equipped to handle your care. If you live in an area without such a team, referral to a center with experience in pituitary surgery is advised.

Complications of pituitary surgery may include loss of normal pituitary function (such as control of the amount of salt and water in the blood, which must be kept more or less the same all the time to avoid cell damage) and — sometimes — infection, bleeding or leakage of spinal fluid from inside the brain cavity through the nose. After surgery, patients generally require blood tests to monitor their levels of sodium and cortisol (a steroid hormone) in the blood during the first several weeks after surgery. They also need follow-up testing of pituitary function and MRI examination of the pituitary several weeks to months after surgery.

In some cases where surgery is ineffective, additional treatment with radiation therapy is used. Radiation therapy for pituitary tumors can take various forms, including stereotactic radiosurgery (Gamma Knife®, proton beam, linear accelerator or Cyberknife®) – a non-surgical radiation therapy that focuses high-power energy on a small area of the body – or conventional radiation therapy. Radiation therapy is best administered in medical centers with specialized expertise. Radiation therapy directed to the pituitary may lead to loss of pituitary function over time, necessitating regular monitoring (including hormone testing) and appropriate hormone replacement therapy, as needed. Otherwise, radiation therapy used for pituitary tumors is generally safe and usually not associated with serious side effects. Your endocrinologist and radiation oncologist will discuss with you the specific indications, benefits and risks of radiation therapy in your particular situation.

Medications may be prescribed in some patients with tumors producing growth hormone or ACTH, generally as a second-line treatment after unsuccessful surgery. In these patients, medications can control hormone excess and, in some cases, shrink tumor size. Medication may also be required to replace the hormones that are deficient due to the pituitary disorder. These medications may include hydrocortisone (“cortisone”) or prednisone to replace inadequate adrenal function, thyroid hormone (levothyroxine) to address hypothyroidism, and sex hormones to replace missing hormones (estrogen and progesterone for women, testosterone for men). Growth hormone replacement is generally necessary to restore appropriate growth in children. In adults with a pituitary disorder, growth hormone deficiency may be associated with symptoms of fatigue, poor quality of life, abnormal fat accumulation and osteoporosis (thinning of the bones). If growth hormone is missing, then its possible use in adults should be discussed in detail with the endocrinologist.

In many cases, lifelong therapy is needed. In all cases, regular monitoring and follow-up is needed under the care of the endocrinologist, who will assure that the medication remains effective and well-tolerated.

Often no therapy is prescribed for small, stable tumors that are not over-secreting any hormones or otherwise causing vision problems or loss of hormone function.

What steps can I take to support my treatment?

After diagnosis, it often becomes necessary to share vital information about your tumor with appropriate medical personnel. Having this information at your fingertips greatly facilitates the efficiency of your medical team. The following is information you should keep updated and accessible:

  • What is the size of the tumor?
  • Is the tumor currently pressing on any vital structures?
  • According to the current blood tests, what hormones are over-secreted (present in excess)?
  • What hormones are under–secreted (deficient)?
  • What are my current symptoms?
  • Have I received any treatments for my pituitary condition? If so, which one(s) and when?

Questions to ask your doctor at each examination:

  • How often should I come back for follow-up?
  • What symptoms would you like me to report to you in between visits?
  • Do I need surgery, continued medication, or radiation therapy?
  • Do you expect that the medication that I am currently on will be required indefinitely?