Triiodothyronine: Difference between revisions
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'''Triiodothyronine''', [[carbon|C<sub>15</sub>]][[hydrogen|H<sub>12</sub>]][[iodine|I<sub>3</sub>]][[nitrogen|N]][[oxygen|O<sub>4</sub>]], also known as '''T<sub>3</sub>''', is a [[thyroid hormone]]. |
'''Triiodothyronine''', [[carbon|C<sub>15</sub>]][[hydrogen|H<sub>12</sub>]][[iodine|I<sub>3</sub>]][[nitrogen|N]][[oxygen|O<sub>4</sub>]], also known as '''T<sub>3</sub>''', is a [[thyroid hormone]]. |
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[[Thyroid-stimulating hormone]] (TSH) activates the production of tetraiodothyronine (T<sub>4</sub>) and T<sub>3</sub>. This process is under regulation. In the [[hypothalamus]], T<sub>4</sub> is converted to T<sub>3</sub>. TSH is inhibited mainly by T<sub>3</sub>. The thyroid gland releases greater amounts of T<sub>4</sub> than T<sub>3</sub>, so plasma concentration of T<sub>4</sub> are 40-fold higher than those T<sub>3</sub>. Most the circulating T<sub>3</sub> is formed peripherally by deiodination of T<sub>4</sub>, a process that involves the removal of iodine from carbon 5 on the outer ring of T<sub>4</sub>. Thus, T<sub>4</sub> acts as |
[[Thyroid-stimulating hormone]] (TSH) activates the production of tetraiodothyronine (T<sub>4</sub>) and T<sub>3</sub>. This process is under regulation. In the [[hypothalamus]], T<sub>4</sub> is converted to T<sub>3</sub>. TSH is inhibited mainly by T<sub>3</sub>. The thyroid gland releases greater amounts of T<sub>4</sub> than T<sub>3</sub>, so plasma concentration of T<sub>4</sub> are 40-fold higher than those T<sub>3</sub>. Most the circulating T<sub>3</sub> is formed peripherally by deiodination of T<sub>4</sub>, a process that involves the removal of iodine from carbon 5 on the outer ring of T<sub>4</sub>. Thus, T<sub>4</sub> acts as prohormone for T<sub>3</sub>. |
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This [[thyroid hormone]] is similar to [[thyroxine]] but with one fewer [[iodine]] [[atom]] per [[molecule]]. In addition, T<sub>3</sub> exhibits greater activity and is produced in smaller quantity. |
This [[thyroid hormone]] is similar to [[thyroxine]] but with one fewer [[iodine]] [[atom]] per [[molecule]]. In addition, T<sub>3</sub> exhibits greater activity and is produced in smaller quantity. |
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Revision as of 22:20, 2 April 2008
Template:Chembox new Triiodothyronine, C15H12I3NO4, also known as T3, is a thyroid hormone.
Thyroid-stimulating hormone (TSH) activates the production of tetraiodothyronine (T4) and T3. This process is under regulation. In the hypothalamus, T4 is converted to T3. TSH is inhibited mainly by T3. The thyroid gland releases greater amounts of T4 than T3, so plasma concentration of T4 are 40-fold higher than those T3. Most the circulating T3 is formed peripherally by deiodination of T4, a process that involves the removal of iodine from carbon 5 on the outer ring of T4. Thus, T4 acts as prohormone for T3.
This thyroid hormone is similar to thyroxine but with one fewer iodine atom per molecule. In addition, T3 exhibits greater activity and is produced in smaller quantity.
It is the most powerful thyroid hormone, and affects almost every process in the body, including body temperature, growth, and heart rate.
Production of T3
In the follicullar lumen, tyrosine residues is iodinated. This reaction requires hydrogen peroxide. Iodine bonds carbon 3 or carbon 5 of tyrosine residues of thyroglobulin in a process called organification of iodine. The iodination of specific tyrosines yields monoiodotyrosine (MIT) and diiodotyrosine (DIT). One MIT and one DIT are enzymatically coupled to form T3. The enzyme is thyroid peroxidase.
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