Thyroxine



Thyroxine is the principal hormone produced by the thyroid gland. It promotes protein synthesis (blending) and growth, and also helps regulate the body's metabolism.

Thyroid Stimulating Hormones

Thyroxine is produced by the thyroid gland in a very complex way. When the blood's thyroxine level is low, the brain's hypothalamus (the part of the brain that regulates body functions) produces a thyrotropin-releasing hormone. This stimulates the pituitary gland to produce thyrotropin. Thyrotropin is a thyroid-stimulating hormone (TSH) that excites the thyroid gland. When the blood's thyroxine level is high, the hypothalamus releases a hormone that inhibits TSH production.

Hyperthyroidism

Hyperthyroidism is a condition caused by an overactive thyroid. The syndrome can cause weight loss, nervousness, and protruding eyes. Called Graves's disease, it was first identified by Irish physician Robert James Graves (1796-1853).

Treating Underactive Glands

German chemist Eugen Baumann (1846-1896) was the first researcher to treat underactive thyroids using extracts made from animal thyroid glands. In 1914 American biochemist Edward Kendall isolated and used the crystalline form of the hormone which was later named thyroxine. In 1926 the British chemist C. R. Harington (1897-1972) determined thyroxine's exact structure and synthesized it out of materials in a laboratory.

Treating Overactive Glands

Today, overactive glands can be treated with medication, removed surgically, or destroyed by radiation. When the gland is removed or destroyed the patient must always take thyroid hormones as replacement therapy. Hormone therapy is also used for underactive glands.

The first widely-used test to measure peoples' thyroid levels was developed in the 1930s by American biochemist Evelyn B. Man (1904-1992). Called the protein-bound iodine test, it soon showed that many "demented" patients in mental hospitals (those having deteriorated mental capabilities) actually had underactive thyroid glands. Treatments with thyroxine helped many of these patients regain normal mental abilities.

Doctors now routinely evaluate an infants' thyroid function by testing blood from newborn babies' umbilical cords. This allows correction of any thyroid gland problem before mental or physical damage occurs.



User Contributions:

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Oct 1, 2010 @ 9:21 pm
My T3 and T4 are in good range. The problem is that a year ago I had a TSH of 3.80 This year my TSH is .03 I am constantly gaining weight would this because of the pituitary. I have had an ultrasound of my thyroid and they have found nodes on my thyroid. I also had a traumatic brain injure in a car accident and wonder if that could have damaged the pituitary. My doctor wants me to go to another endocrinologist what can I ask and expect he will look for?
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Apr 22, 2011 @ 1:13 pm
well my TSH rate is 24.00 and dr. prescribed me thyroxine is it rite for me..??
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May 5, 2011 @ 8:08 am
I WANT TO KNOW HOW THYROXINE RELATES WITH TEMPERATURE AND THE ENVIRONMENT. THAT IS HOW IT AFFECTS THEM AND HOW THEY AFFECT THYROXINE
Fartuunhargaanti
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Dec 2, 2011 @ 4:04 am
I wan't to tell me the effects and benifit of tri-iodothymine and thyroxine

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