What Causes the Overproduction of Hormones that Result in Hyperthyroidism?
By lb50 on February 22, 2016
Hyperthyroidism is a disease where a person has an overactive thyroid that produces too much thyroid hormones. The thyroid, the part of the body affected by this condition, is the largest gland in the endocrine system, tasked to produce hormones necessary for regulating important body functions such as metabolism and calcium and phosphate absorption. The thyroid produces 3 hormones: thyroxine (T4), triiodothyronine (T3) and calcitonin.
To understand the conditions that cause hyperthyroidism, one first has to understand the complicated process that goes into the creation of thyroid hormones and their functions in the body.
Thyroid Hormone Production and Functions
Of the 3 hormones produced by the thyroid, 2 are used to help regulate the rate of metabolism in the body. These are T4 and T3, also called metabolic hormones. Both are produced from iodine, a trace mineral, and tyrosine, an amino acid, absorbed by the thyroid. Just like their names suggest, T4 or thyroxine has 4 iodine molecules, while T3 or triiodothyronine has 3. The metabolic hormones produced by the thyroid signal every cell in the body to increase cellular activity and metabolism. The signal affects breathing rate and heart rate, functions of the digestive and nervous systems, and a person’s weight, temperature, and energy use, among other important body processes. The release of metabolic thyroid hormones is regulated by the thyroid-stimulating hormone (TSH) from the pituitary gland. The release of THS, in turn, is dependent on a hormone produced by the hypothalamus.
The third thyroid hormone, calcitonin, lowers the level of calcium and phosphate in the blood. It promotes the formation of bones by instructing the body to absorb calcium into the bone matrix.
Causes of Hyperthyroidism
The overproduction of thyroid hormones can be cause by several conditions.
- Graves’ Disease, an autoimmune disorder where the body overproduces an antibody called thyroid-stimulating immunoglobulin (TSI), is the most common cause of hyperthyroidism. Instead of targeting foreign bodies such as bacteria and viruses, the antibody attacks the thyroid and the tissue behind the eyes. Also, the antibody mimics the action of the TSH and signals the thyroid to release more hormones.
- Toxic nodular or multinodular goiter is a disease where one or more nodules in the thyroid are enlarged and produce too much thyroid hormones. It is the second most common cause of hyperthyroidism. Multinodular goiter increases one’s risk for thyroid cancer. The cause for this condition is still unknown, but it has been linked to iodine deficiency and genetic factors.
- Thyroiditis or the inflammation of the thyroid, can cause stored thyroid hormones to leak into the bloodstream. The cause of thyroiditis is still unknown.
- Too much iodine in one’s diet can also cause hyperthyroidism. Remember that thyroid metabolic hormones are made from iodine. Having too much of this mineral in one’s system can cause the thyroid to overproduce hormones that increase the rate of one’s metabolism.
If you are experiencing any of the symptoms of hyperthyroidism, the best move is to consult with your doctor in order find and cure the underlying cause of disease.
References:
- http://www.endocrineweb.com/conditions/hyperthyroidism/hyperthyroidism-overview-overactive-thyroid
- http://www.mayoclinic.org/diseases-conditions/hyperthyroidism/basics/definition/con-20020986
- http://www.mayoclinic.org/diseases-conditions/graves-disease/basics/causes/con-20025811
- https://www.nlm.nih.gov/medlineplus/ency/article/000317.htm
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