pituitary and pineal glands

pituitary gland

The pituitary gland is a tiny organ, the size of a pea, found at the base of the brain. As the “master gland” of the body, it produces many hormones that travel throughout the body, directing certain processes or stimulating (causing) other glands to produce other hormones.

The pituitary gland makes or stores many different hormones. The following hormones are made in the anterior (front part) of the pituitary gland:

• Prolactin - Prolactin stimulates breast milk production after childbirth. It also affects sex hormone levels from ovaries in women and from testes (testicles) in men, as well as fertility.
• Growth hormone (GH) - GH stimulates growth in childhood and is important for maintaining a healthy body composition and well-being in adults. In adults, GH is important for maintaining muscle mass and bone mass. It also affects fat distribution in the body.
• Adrenocorticotropin (ACTH) - ACTH stimulates the production of cortisol by the adrenal glands—small glands that sit on top of the kidneys. Cortisol, a "stress hormone," is vital to our survival. It helps maintain blood pressure and blood glucose (sugar) levels, and is produced in larger amounts when we’re under stress—especially after illness or injury.
• Thyroid-stimulating hormone (TSH) - TSH stimulates the thyroid gland to produce thyroid hormones, which regulate the body's metabolism, energy balance, growth, and nervous system activity.
• Luteinizing hormone (LH) - LH stimulates testosterone production in men and egg release (ovulation) in women.
• Follicle-stimulating hormone (FSH) - FSH promotes sperm production in men and stimulates the ovaries to produce estrogen and develop eggs in women. LH and FSH work together to enable normal function of the ovaries and testes.

The following hormones are stored in the posterior (back part) of the pituitary gland:

• Antidiuretic hormone (ADH) - ADH, also called vasopressin, regulates water balance in the body. It conserves body water by reducing the amount of water lost in urine.
• Oxytocin – Oxytocin causes milk to flow from the breasts in breastfeeding women, and may also help labor to progress.

Pituitary Tumors

The most frequent type of pituitary disorder is a pituitary glandtumor. These tumors are fairly common in adults. They are not brain tumors and are almost always benign (that is, not cancer). In fact, cancerous tumors of this sort are extremely rare.

There are two types of tumors—secretory and non-secretory. Secretory tumors produce too much of a hormone normally made by the pituitary, and non-secretory tumors do not. Both types of tumors can cause problems if they are large and interfere with normal function of the pituitary gland and/or nearby structures in the brain.

The problems caused by pituitary tumors fall into three general categories:

1. Hypersecretion: Too much of any hormone in the body is caused by a secretory pituitary tumor.
2. Hyposecretion: Too little of any hormone in the body can be caused by a large pituitary tumor, which interferes with the pituitary gland’s ability to produce hormones. Hyposecretion can also result from surgery or radiation of a tumor.
3. Tumor mass effects: As a pituitary tumor grows and presses against the pituitary gland or other areas in the brain, it may cause headaches, vision problems, or other health effects.

Injuries, certain medications, bleeding inside or close to the pituitary, and other conditions can also affect the pituitary gland. Loss of normal pituitary function also can occur after major head trauma.

Editors:

Anne Klibanski, MD
Massachusetts General Hospital
Harvard Medical School

Nicholas Tritos, MD
Massachusetts General Hospital
Harvard Medical School

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About the adrenal glands

Each person has two adrenal glands; one located on top of each of the body’s two kidneys. These glands are important to the body’s endocrine (hormonal) system. Each adrenal gland has two main parts that function separately:

Adrenal cortex. The outer part of the adrenal gland is called the cortex. The adrenal cortex makes three main hormones: cortisol, aldosterone, and dehydroepiandrosterone (DHEA). These hormones carefully control metabolism and body characteristics, such as hair growth and body shape.

Adrenal medulla. The gland’s inner part is called the medulla. The adrenal medulla makes three other hormones: epinephrine, norepinephrine, and dopamine. These hormones control the body’s responses to stress, including the “fight or flight” adrenaline surge.

Types of adrenal gland tumors

A tumor begins when normal cells change and grow uncontrollably, forming a mass. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can spread to other parts of the body. A benign tumor means the tumor will not spread.

A tumor can start in an adrenal gland, called a primary adrenal tumor, or it can begin in another organ, such as the lungs, and then spread to the adrenal glands. An adrenal gland tumor can sometimes overproduce hormones. When it does, the tumor is called a functioning tumor. An adrenal gland tumor that does not produce hormones is called a nonfunctioning tumor. The symptoms and treatment of an adrenal gland tumor depend on whether the tumor is functioning or nonfunctioning, what hormone(s) is overproduced, and whether the tumor is a primary adrenal gland tumor or if the cancer has spread from another organ.

This section focuses on primary adrenal gland tumors, which include the following:

Adenoma. Also called an adrenocortical adenoma, this is the most common type of adrenal gland tumor. It is a noncancerous, nonfunctioning tumor of the adrenal cortex. An adenoma usually does not cause symptoms and, if it is small, often does not need treatment.

Adrenocortical carcinoma. Although rare, adrenocortical carcinoma is the most common type of cancerous adrenal gland tumor. It is also known as adrenal cortical carcinoma. Approximately four to 12 out of one million people develop this type of tumor, which begins in the adrenal cortex. Adrenocortical carcinoma can be a functioning or nonfunctioning tumor. If the tumor is functioning, it may produce more than one hormone.

Neuroblastoma. This is a type of childhood cancer that can begin in the adrenal medulla. .

Pheochromocytoma. This type of neuroendocrine tumor most often begins in the adrenal medulla.

What is adrenal fatigue

Adrenal fatigue is a collection of signs and symptoms, known as a syndrome, that results when the adrenal glands function below the necessary level. Most commonly associated with intense or prolonged stress, it can also arise during or after acute or chronic infections, especially respiratory infections such as influenza, bronchitis or pneumonia. As the name suggests, its paramount symptom is fatigue that is not relieved by sleep but it is not a readily identifiable entity like measles or a growth on the end of your finger. You may look and act relatively normal with adrenal fatigue and may not have any obvious signs of physical illness, yet you live with a general sense of unwellness, tiredness or "gray" feelings. People experiencing adrenal fatigue often have to use coffee, colas and other stimulants to get going in the morning and to prop themselves up during the day.

This syndrome has been known by many other names throughout the past century, such as non-Addison's hypoadrenia, sub-clinical hypoadrenia, neurasthenia, adrenal neurasthenia, adrenal apathy and adrenal fatigue. Although it affects millions of people in the U.S. and around the world, conventional medicine does not yet recognize it as a distinct syndrome.

Adrenal fatigue can wreak havoc with your life. In the more serious cases, the activity of the adrenal glands is so diminished that you may have difficulty getting out of bed for more than a few hours per day. With each increment of reduction in adrenal function, every organ and system in your body is more profoundly affected. Changes occur in your carbohydrate, protein and fat metabolism, fluid and electrolyte balance, heart and cardiovascular system, and even sex drive. Many other alterations take place at the biochemical and cellular levels in response to and to compensate for the decrease in adrenal hormones that occurs with adrenal fatigue. Your body does its best to make up for under-functioning adrenal glands, but it does so at a price.