Having an overactive pituitary gland is called hyperpituitarism. Noncancerous (benign) tumors usually cause this condition by making the gland produce too much or too little of the hormones that control growth, reproduction and metabolism. The hormonal changes cause a range of different disorders, from gigantism in children to hyperthyroidism in adults.
When your pituitary gland is overactive, it releases excessive amounts of certain types of pituitary hormones into your bloodstream. A noncancerous (benign) tumor in the gland, called a pituitary adenoma, is usually the cause of this condition. An overactive pituitary gland can cause a variety of disorders that affect growth, metabolism, reproduction and other vital body functions.
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The pituitary gland plays a major role in controlling how your body works. It’s a pea-sized, cherry-shaped endocrine gland located near the base of your brain. Endocrine glands release (secrete) hormones into your bloodstream that control your body’s functions. Your endocrine system affects almost every cell and organ in your body. Sometimes the pituitary is called the “master gland” because it controls the activity of other endocrine glands. Most importantly, it controls the activity of your thyroid gland, adrenal gland and gonadal glands (ovaries or testes).
Think of your pituitary gland like a thermostat. The thermostat performs constant temperature checks in your home to keep you comfortable. It sends signals to your heating and cooling systems to turn up or down — and by how many degrees — to keep air temperatures constant. Your pituitary gland monitors your body functions in much the same way. Your pituitary gland sends signals to your organs and glands to tell them what functions are needed and when. The right settings for your body depend upon many things, including your sex, weight distribution and how active you are.
Blood vessels connect your pituitary gland to a part of your brain called the hypothalamus. Your brain tells your pituitary gland to increase or decrease the secretion of certain hormones.
Your pituitary gland consists of three parts: the anterior, intermediate and posterior lobes.
Your anterior lobe makes up about 80% of your pituitary gland and releases these hormones:
Your intermediate lobe secretes only one hormone:
Your posterior lobe stores and releases two hormones that your hypothalamus produces:
There are a number of adrenal disorders that can develop as a result of hyperpituitarism (overactive pituitary gland):
Depending on the disorder, some are more common than others. Some of the most common conditions are:
Hyperpituitarism is rare in children. If it does occur, it typically results from pituitary microadenoma, a small (less than 10 millimeters), benign tumor. The most common pituitary adenoma found in childhood are prolactinomas, which occur in approximately half of all cases. Prolactinomas originate from stem cells of hormone-producing glands, which explains why they may secrete hormones. Several inherited syndromes — including multiple endocrine neoplasia type 1 (MEN1), Carney complex and familial isolated pituitary adenomas — appear to cause prolactinomas.
The disorders caused by prolactinomas depend on the sex and age of the child:
If left untreated, the conditions associated with hyperpituitarism can cause serious health problems. That’s why it’s important to talk to your healthcare provider if you experience symptoms of these disorders.
The disorders related to an overactive pituitary gland have different symptoms.
Cortisol is necessary to keep your blood pressure and blood sugar levels even and also to help turn the food you eat into energy, among other important roles. But too much of a good thing can be bad, and that’s the case with the copious amounts of cortisol your body releases when you have Cushing’s syndrome.
Symptoms of Cushing’s syndrome may include:
Acromegaly occurs when your body produces more growth hormone than it needs. The extra growth hormone causes abnormal growth and other changes. Acromegaly can cause:
In children and adolescents, excessive levels of growth hormone can result in a condition called gigantism. Children with this condition may have unusually long arms and legs and may grow to heights of 7 to 8 feet or more.
If a benign pituitary adenoma causes your thyroid to release too much thyroid stimulating hormone (TSH) into your bloodstream, you may develop hyperthyroidism. Symptoms of hyperthyroidism may include:
Rarely, a benign pituitary adenoma can cause your thyroid to not make enough thyroid hormone due to damage to normal pituitary gland cells. When this happens, you may develop hypothyroidism. Symptoms may include:
If you have a benign tumor on your pituitary gland, it can cause too much prolactin to be released into your blood. Some symptoms — like headaches — are experienced by both sexes. When the prolactinoma is left untreated, it can grow large and press down on the optic nerve. This can cause impaired vision — or even blindness. Other symptoms depend upon your sex:
Most cases of hyperpituitarism (overactive pituitary gland) are caused by a pituitary tumor. No one knows what causes these tumors but possible culprits include:
Your healthcare provider will ask about your medical history and any symptoms you're having. Lab tests and scans may be ordered to measure the levels of hormones in your blood or urine or to detect the presence of a tumor. Tests may include:
Your healthcare provider may prescribe one or a combination of different treatments including:
Depending on your condition, you may simply be given medications to regulate your hormone levels. Your healthcare provider may use drugs to shrink large tumors before surgery or in cases where surgery isn’t an option.
For acromegaly or Cushing’s syndrome: People with acromegaly or Cushing’s syndrome may undergo a surgical procedure called a transsphenoidal adenomectomy. To reach your pituitary gland and remove the tumor, your surgeon will make a small cut through your nose or upper lip. Though this procedure is very delicate, it has a success rate greater than 80% when performed by an experienced surgeon. Transsphenoidal surgery is most effective for small tumors (less than 10 millimeters, or ⅜ inch, in diameter). This procedure is considered safe, but all surgeries have risks, which your surgeon should talk about with you.
For prolactinomas: People with prolactinomas may need surgery to remove the tumor and take the pressure off their optic nerve. This may be done through your nose and sphenoid sinus (transsphenoidal surgery) or through open surgery (a craniotomy).
Radiation may be used for people who can’t have surgery or who have some tumor tissue left after surgery which doesn’t respond to medication. There are two approaches to radiation:
No cure is known for an overactive pituitary gland, but in many cases it can be treated and its symptoms managed.
There's no specific way to prevent an overactive pituitary gland. However, your symptoms depend upon the disorder for which you are being treated. Since your health and symptoms vary on a regular basis, it’s important to take note of changes in how you feel. Keep in contact with your healthcare provider to stay ahead of any new or worsening symptoms of your condition. Keeping the communication lines open will help keep your condition in check.
The outlook for an overactive pituitary gland is good for most people. Though some conditions may require you to take medications or be monitored on an ongoing basis, many people learn to manage their symptoms well and lead healthy, happy and productive lives. Rarer conditions, such as Cushing’s syndrome and acromegaly, need more serious treatment and outlooks are different for each person. If you have been diagnosed with prolactinomas — which tend to come back — you may require long-term medicines to manage your condition and follow-ups with your healthcare provider.
A note from Cleveland Clinic
The hormone changes that come with hyperpituitarism (overactive pituitary gland) can disrupt your life. It might help if you keep a record of your symptoms, along with dates, and take this journal to your healthcare provider. If you’ve been diagnosed with any condition related to an overactive pituitary gland, tell your provider about any changes in symptoms or new symptoms that you experience.
Last reviewed by a Cleveland Clinic medical professional on 05/23/2022.
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