Triiodothyronine: Difference between revisions

Latest revision as of 23:52, 9 February 2025

A hormone produced by the thyroid gland

Triiodothyronine (T3) is a thyroid hormone that plays vital roles in the body's metabolic rate, heart and digestive functions, muscle control, brain development, and maintenance of bones. It is one of the two main hormones produced by the thyroid gland, the other being thyroxine (T4).

Structure and Function[edit]

Triiodothyronine is a hormone that contains three iodine atoms, hence the name. It is derived from the amino acid tyrosine. T3 is more potent than T4 and is considered the active form of thyroid hormone. It influences almost every physiological process in the body, including growth and development, metabolism, body temperature, and heart rate.

Synthesis[edit]

T3 is produced by the thyroid gland and also by the conversion of T4 into T3 in peripheral tissues. This conversion is catalyzed by enzymes called iodothyronine deiodinases.

Mechanism of Action[edit]

T3 acts on target tissues by binding to nuclear receptors, which then influence the expression of specific genes. This process regulates various metabolic pathways and is crucial for normal development and metabolism.

Regulation[edit]

The production and release of T3 are regulated by the hypothalamic-pituitary-thyroid axis. The hypothalamus releases thyrotropin-releasing hormone (TRH), which stimulates the pituitary gland to secrete thyroid-stimulating hormone (TSH). TSH then stimulates the thyroid gland to produce T3 and T4.

Clinical Significance[edit]

Abnormal levels of T3 can lead to various health issues. Hyperthyroidism is characterized by excessive levels of T3, leading to symptoms such as weight loss, increased heart rate, and anxiety. Conversely, hypothyroidism is marked by insufficient T3 levels, causing fatigue, weight gain, and depression.

Related Pages[edit]

References[edit]

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-'''Triiodothyronine''', also known as '''T3''', is a [[thyroid hormone]] that plays crucial roles in the body's overall [[metabolism]], growth, and development. It is produced by the [[thyroid gland]] and is the more biologically active hormone out of the two thyroid hormones. The other hormone is [[thyroxine]] (T4), which is converted into T3 in the body's peripheral tissues.
+{{Short description|A hormone produced by the thyroid gland}}
+{{Use dmy dates|date=October 2023}}
-== Production and Function ==
+'''Triiodothyronine''' ('''T3''') is a [[thyroid hormone]] that plays vital roles in the body's metabolic rate, heart and digestive functions, muscle control, brain development, and maintenance of bones. It is one of the two main hormones produced by the thyroid gland, the other being [[thyroxine]] (T4).
-Triiodothyronine is primarily produced from the deiodination of thyroxine (T4) in peripheral tissues. This process is regulated by the [[thyroid-stimulating hormone]] (TSH), which is released from the [[pituitary gland]]. T3 then enters cells and binds to [[nuclear receptors]], influencing the transcription of various genes.
+==Structure and Function==
+Triiodothyronine is a [[hormone]] that contains three [[iodine]] atoms, hence the name. It is derived from the amino acid [[tyrosine]]. T3 is more potent than T4 and is considered the active form of thyroid hormone. It influences almost every physiological process in the body, including growth and development, metabolism, body temperature, and heart rate.
-The functions of T3 include increasing the basal metabolic rate, affecting protein synthesis, helping to regulate long bone growth, and aiding in brain development. It also plays a role in maintaining body temperature, heart rate, and blood pressure.
+==Synthesis==
+[[File:Thyroid_hormone_synthesis.png|thumb|right|300px|Synthesis of thyroid hormones.]]
+T3 is produced by the [[thyroid gland]] and also by the conversion of T4 into T3 in peripheral tissues. This conversion is catalyzed by enzymes called [[iodothyronine deiodinases]].
-== Clinical Significance ==
+==Mechanism of Action==
+T3 acts on target tissues by binding to nuclear receptors, which then influence the expression of specific genes. This process regulates various metabolic pathways and is crucial for normal development and metabolism.
-Abnormal levels of T3 can lead to various medical conditions. High levels can result in [[hyperthyroidism]], characterized by weight loss, increased heart rate, and anxiety. On the other hand, low levels can lead to [[hypothyroidism]], which can cause fatigue, weight gain, and depression.
+==Regulation==
+The production and release of T3 are regulated by the [[hypothalamic-pituitary-thyroid axis]]. The [[hypothalamus]] releases [[thyrotropin-releasing hormone]] (TRH), which stimulates the [[pituitary gland]] to secrete [[thyroid-stimulating hormone]] (TSH). TSH then stimulates the thyroid gland to produce T3 and T4.
-Measurement of T3 levels is part of the diagnostic process for thyroid disorders. It is also used to monitor the effectiveness of treatment for these conditions.
+==Clinical Significance==
+Abnormal levels of T3 can lead to various health issues. [[Hyperthyroidism]] is characterized by excessive levels of T3, leading to symptoms such as weight loss, increased heart rate, and anxiety. Conversely, [[hypothyroidism]] is marked by insufficient T3 levels, causing fatigue, weight gain, and depression.
-== See Also ==
+==Related Pages==
+* [[Thyroid hormone]]
+* [[Thyroxine]]
+* [[Hypothyroidism]]
+* [[Hyperthyroidism]]
-* [[Thyroid function tests]]
+==References==
-* [[Thyroid disease]]
+{{Reflist}}
-* [[Thyroid hormones]]
-== References ==
+[[File:Liothyronine2DCSD.svg|thumb|right|200px|Chemical structure of triiodothyronine.]]
+[[File:Iodothyronine_deiodinase.png|thumb|right|200px|Iodothyronine deiodinase enzyme.]]
+[[File:Thyroid_system.svg|thumb|right|300px|Diagram of the thyroid system.]]
+[[File:Thyroid_system.png|thumb|right|300px|Thyroid system overview.]]
-<references />
+[[Category:Thyroid hormones]]
-[[Category:Thyroid]]
-[[Category:Hormones]]
-[[Category:Endocrinology]]
-{{stub}}