Catecholamine

Catecholamines are compounds that function as hormones and neurotransmitters. They contain a dihydroxy (two hydroxal groups) benzene ring and are derived from tyrosine, an amino acid. Catecholamines are produced in the adrenal glands, which are found on the top of each kidney. The glands release the compounds when a person is subjected to emotional or physical stress. The main types of catecholamine are dopamine, epinephrine (adrenaline), and norepinephrine. These hormones are released during times of high stress and certain illnesses. Physicians can order blood or urine tests to check the levels of catecholamine in their patients. This is done to test for specific problems, including several very rare types of tumors.

Background

Hormones are one of the ways different parts of the body communicate with one another. They are chemicals that are produced in different glands, or body organs designed to produce these special chemicals. The hormones are released into the bloodstream and circulate throughout the body, where they trigger specific reactions. The human body has fourteen glands that control a wide range of activities.

Catecholamine is produced in the adrenal glands. The adrenal glands are two triangular-shaped glands that are located on each kidney. Each gland is about 1.5 by 3 inches (or just under 4 by 8 centimeters) in size. Their name identifies their location: ad means "at or near" and renal is a derivative of the Latin word for kidney.

The adrenal glands have two parts, the adrenal cortex and the adrenal medulla. The adrenal cortex releases hormones that are necessary for sustaining life, such as hydrocortisone, which helps regulate how the body turns food into energy, and corticosterone, which helps maintain the body's immune system. The adrenal medulla produces nonessential hormones that are not life sustaining. Catecholamine is produced in the adrenal medulla.

Overview

Catecholamines are important in the body since they can function as both hormones and neurotransmitters. Neurotransmitters send signals throughout the body from one nerve cell to another. One important catecholamine is epinephrine, also known as adrenaline. Epinephrine is a hormone and neurotransmitter that prepares the body to respond to a threat and is part of what is known as the "fight or flight" response. When danger is perceived, the brain notifies the body to release epinephrine. Once produced and released by the adrenal glands, epinephrine triggers the production of glucose, which the body can use as quick fuel. It also signals the heart to beat faster and increase circulation, sends less blood to the skin and other nonessential locations, and increases the breathing rate. Together, this prepares the body either to fight the danger or to flee from it.

Norepinephrine, another catecholamine, also helps to increase the rate of respiration and circulation as well as the amount of fuel available to the body in the form of glucose and is part of the body's response to an emergency. It also increases focus and the ability to pay attention. People with low levels of norepinephrine have problems focusing and sometimes have conditions such as attention-deficit hyperactivity disorder and depression.

The catecholamine dopamine affects a number of functions, including memory, attention, sleep, mood, pleasure-seeking behavior, and learning. It is also partially responsible for movement; therefore, too much dopamine can cause uncoordinated movements while too little can cause the body to twitch or have tics (small, random movements). Irregularities in dopamine levels can result in serious medical conditions. For instance, in patients with Parkinson's disease, less dopamine is produced by the brain, causing a person to have less ability to regulate his or her body movements. Dopamine deficiency also plays a role in several mental disorders, including schizophrenia and depression.

Catecholamine levels can change dramatically due to physical or emotional stress, triggering reactions similar to those experienced when a person is in danger. Levels of the hormones are also affected by exercise, low blood sugar levels, blood loss, the temperature around the body, and changing position from sitting to standing or vice versa. Some foods can also affect catecholamine levels, including coffee, tea, chocolate, bananas, citrus foods, and items containing vanilla. Nicotine and cocaine can also increase catecholamine levels. Medications that affect catecholamine levels include acetaminophen, some blood pressure medications, amphetamines, and some antidepressants.

In addition to the problems that can be caused by too much or too little of these hormones, the presence of high levels of catecholamines can indicate a number of different health conditions. These include extreme stress and anxiety, some types of enzyme deficiencies, a condition called Menkes syndrome, and baroreflex failure, which is a rare condition in which blood pressure levels fluctuate. High levels can also result in high blood pressure, which might be experienced as chest pain, anxiety, a rapid and pounding heartbeat, sweating, and headaches.

To determine if catecholamine levels are high, physicians can order blood or urine tests. Both tests require the patient to avoid foods that can affect catecholamine levels, as well as tobacco and the medications that are known to affect catecholamine production. Some foods and medications may need to be avoided for two full weeks before testing, depending on how quickly their effect on the adrenal glands dissipates. Blood tests may require fasting for twelve or more hours beforehand.

Urine testing to determine catecholamine levels can involve a single catch of urine. However, a collection of urine over twenty-four hours is more common. The test is done at home. For twenty-four hours, all the urine the patient produces is collected in a container that includes a preservative and is provided by the physician's office. Twenty-four-hour testing is done because a person's levels of catecholamine can vary dramatically throughout the day. A long testing period considers this.

While high levels of catecholamine can be an indicator of a number of conditions, some of them serious, testing for this compound is not usually the only test performed. It is simply the beginning of a process of diagnosis. Many of the conditions indicated by high catecholamine levels are treatable.

Bibliography

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