Pituitary Gland Overview

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 as well as prolactin, which causes breast milk production in women after the birth of a child, and growth hormone. 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. 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. It is connected to the brain by a thin piece of tissue called the pituitary stalk and connected to a part of the brain called the hypothalamus. The pituitary stalk is called the infundibulum. The pituitary gland is 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 from the hypothalamus – but it does release vasopressin, which is a hormone that controls salt and water balance in the body as well as maintains blood pressure. 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 or less of a specific hormone.

Anterior Lobe Hormones:
• Adrenocorticotropic Hormone (ACTH): ACTH stimulates the adrenal glands to grow and produce cortisol and other hormones.
• Follicle-Stimulation Hormone (FSH): FSH works with LH to ensure normal functioning of the ovaries and testes.
• Luteinizing Hormone (LH): LH works with FSH 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, affects fat distribution and sense of well-being.
• Prolactin: Prolactin stimulates breast milk production
• Thyroid-Stimulating Hormone (TSH): TSH stimulates the thyroid gland to grow and produce hormones.

Posterior Lobe Hormones:
The posterior lobe contains the ends of the 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.

• Anti-Diuretic Hormone (ADH): This hormone prompts the kidneys to increase water absorption in the blood and also controls salt balance.
• Oxytocin: Oxytocin is involved in a variety of processes, such as contracting the uterus during childbirth and stimulating breast milk expression.

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 are harmless – pituitary tumors can disrupt the gland’s normal ability to release anterior as well as posterior lobe 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. Other clinical situations can cause problems in the pituitary such as infection, bleeding into the pituitary, trauma to the pituitary, cancer which invades the pituitary and other rare problems. Another pituitary disorder is a rare condition 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.

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.