The pituitary gland is central to our well-being. It is the master gland of the entire body. It produces (secretes) many hormones that stimulate glands in the body to produce other hormones or to complete certain actions. A gland is an organ that makes hormones, substances which function as messengers and are carried to other parts of your body, where they have an effect or stimulate an action.
The pituitary gland makes many different hormones:
Prolactin - Prolactin stimulates milk production from the breasts after childbirth to enable nursing and can affect sex hormone levels from the ovaries in women and the testes in men.
Growth hormone or GH - GH stimulates growth in childhood and is important for maintaining a healthy body composition and well-being in adults. In adults it is important for maintaining muscle mass as well as bone mass. It also affects fat distribution in the body.
Adrenocorticotropin or ACTH - ACTH stimulates production of cortisol by the adrenal glands. Cortisol, a so-called "stress hormone" is vital to survival. It helps maintain blood pressure and blood glucose levels.
Thyroid-stimulating hormone or TSH - TSH stimulates the thyroid gland, which regulates the body's metabolism, energy, growth and development, and nervous system activity. This hormone also is vital to your survival.
Antidiuretic hormone or ADH - ADH, also called vasopressin, is stored in the back part of the pituitary gland and regulates water balance. If this hormone is not secreted properly, this can lead to a diabetes insipidus (different from diabetes mellitus which affects glucose) because your kidneys are not working well.
Luteinizing hormone or LH - LH regulates testosterone in men and estrogen in women.
Follicle-stimulating hormone or FSH - FSH promotes sperm production in men and stimulates the ovaries to enable ovulation in women. LH and FSH work together to cause normal function of the ovaries and testes.
The most frequent cause of pituitary disorders is pituitary tumors. The pituitary gland is made of several cell types. Each cell type releases one of the hormones mentioned above. Sometimes these cells grow too much or produce small growths.
These growths are called pituitary tumors, and they are fairly common in adults. These are not brain tumors and are not a form of cancer. Cancerous tumors of this sort are extremely rare. Pituitary tumors can interfere with the normal formation and release of hormones, however. In addition, some pituitary tumors make too much of the type of hormone produced by the pituitary cells forming the tumor.
Two types of tumors exist: secretory and non-secretory. Secretory tumors produce too much of a hormone. Non-secretory tumors cause problems because of their large size or because they interfere with normal function of the pituitary gland.
The problems caused by pituitary tumors fall into three categories:
- Hypersecretion - Too much hormone is secreted into the body. This is usually caused by a secretory tumor. Common secretory tumors make too much prolactin. Other tumors make too much of the pituitary hormones which stimulate growth, the adrenal gland or the thyroid. Tumors making too much of the hormones stimulating the ovaries or testes are extremely rare.
- Hyposecretion - Too little hormone is secreted into the body. This is usually caused by a non-secretory tumor, which interferes with the ability of the normal pituitary gland to make hormones. It can also be caused by a secretory tumor which is large. It can also result from therapy of a tumor with surgery and/or radiation treatment.
- Tumor mass effects - As the tumor grows and presses against the normal pituitary gland or other areas in the brain, you may have headaches, vision problems, or hypo secretion. Tumor mass effects can be seen in any type of pituitary tumor that grows large enough. Injuries, certain medications, and other conditions can also affect the pituitary gland. Loss of normal pituitary function has been reported after major head trauma. The prolonged use of steroid medications such as prednisone can suppress levels of ACTH and result in adrenal insufficiency (a lack of cortisol production) if abruptly discontinued, which must be replaced until ACTH and adrenal function returns. A number of psychiatric medications can lead to an increase in prolactin levels.
NOTE: If you think you have a problem with your pituitary gland, it is important that you see a pituitary specialist. An endocrinologist is an expert in hormone-related conditions, and some endocrinologists make the pituitary gland their specialty. You may be referred to other doctors if you need surgery or radiation treatments.