An Overview of the Pituitary Gland

The Endocrine System’s Master Gland

Pituitary Gland Essentials
  • The hormones of the pituitary gland help regulate the functions of other endocrine glands.
  • The pituitary gland has two parts—the anterior lobe and posterior lobe—that have two very separate functions.
  • The hypothalamus sends signals to the pituitary to release or inhibit pituitary hormone production.
 
The pituitary gland is often dubbed the “master gland” because its hormones control other parts of the endocrine system, namely the thyroid gland, adrenal glands, ovaries, and testes. However, the pituitary doesn’t entirely run the show.
 
In some cases, the hypothalamus signals the pituitary gland to stimulate or inhibit hormone production. Essentially, the pituitary acts after the hypothalamus prompts it.
 
Anatomy of the Pituitary Gland
The pituitary gland is only about 1/3 of an inch in diameter (that’s about as large as a pea) and located at the base of the brain.
 
Since their functions are so intertwined, it’s no surprise that the hypothalamus and pituitary are located near each other. They’re actually connected by the pituitary stalk, or more technically, the infundibulum.
 
The pituitary glands are made of the anterior lobe and posterior lobe. The anterior lobe produces and releases hormones. The posterior lobe does not produce hormones per se—this is done by nerve cells in the hypothalamus—but it does release them into the circulation.
 
Hormones of the Pituitary Gland
The hormones of the pituitary gland send signals to other endocrine glands to stimulate or inhibit their own hormone production. For example, the anterior pituitary lobe will release adrenocorticotropic hormone (ACTH) to stimulate cortisol production in the adrenal glands when you’re stressed.
 
The anterior lobe releases hormones upon receiving releasing or inhibiting hormones from the hypothalamus. These hypothalamic hormones tell the anterior lobe whether to release more of a specific hormone or stop production of the hormone.
 
Anterior Lobe Hormones:
  • Adrenocorticotropic hormone (ACTH): ACTH stimulates the adrenal glands to produce hormones.
  • Follicle-stimulating hormone (FSH): FSH works with LH to ensure normal functioning of the ovaries and testes.
  • Growth hormone (GH): GH is essential in early years to maintaining a healthy body composition and for growth in children. In adults, it aids healthy bone and muscle mass and affects fat distribution.
  • Luteinizing hormone (LH): LH works with FSH to ensure normal functioning of the ovaries and testes.
  • Prolactin: Prolactin stimulates breast milk production.
  • Thyroid-stimulating hormone (TSH): TSH stimulates the thyroid gland to produce hormones.
 
The posterior lobe contains the ends of nerve cells coming from the hypothalamus. The hypothalamus sends hormones directly to the posterior lobe via these nerves, and then the pituitary gland releases them.
 
Posterior Lobe Hormones:
  • Anti-diuretic hormone (ADH): This hormone prompts the kidneys to increase water absorption in the blood.
  • Oxytocin: Oxytocin is involved in a variety of processes, such as contracting the uterus during childbirth and stimulating breast milk production.
 
Diseases and Disorders of the Pituitary Gland
Pituitary tumors are the most common pituitary disorder, and many adults have them. However, they are not, in the great majority of cases, life threatening. But that doesn’t mean they’re harmless—pituitary tumors can disrupt the gland’s normal ability to release hormones.
 
There are two types of pituitary tumors—secretory and non-secretory. Secretory tumors secrete too much of a hormone, and non-secretory tumors don’t secrete excess hormone.
 
These hormonal imbalances can cause problems in many different areas of the body. If you have a secretory tumor that is overproducing thyroid-stimulating hormone, for instance, you will experience hyperthyroidism.
 
Another pituitary disorder is known as pituitary apoplexy. In some cases, pituitary function can be suddenly disrupted (due to bleeding or trauma), creating a life-threatening shortage of vital hormones.
 
If you think you may have a problem with your pituitary gland, you should talk to an endocrinologist. He or she will help diagnose and treat your hormone-related condition.
 
The pituitary gland is immensely important to the overall function of your endocrine system—and to your overall health. By working with the hypothalamus, the pituitary gland ensures that all your body’s internal processes work as they should.