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Difference between revisions of "Thyrotropin Releasing Hormone"

 
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''Synonym: TRH'' <BR>
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'''''German''': [[:de:Thyrotropin Releasing Hormone|Thyrotropin Releasing Hormone]]''
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==Definition==
 
==Definition==
 
'''Thyrotropin releasing hormone''' (TRH) is a signalling substance that is produced in several organ systems. There it plays an important role in their respective [[Systeomics|systeomics]].
 
'''Thyrotropin releasing hormone''' (TRH) is a signalling substance that is produced in several organ systems. There it plays an important role in their respective [[Systeomics|systeomics]].
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===Hypothalamo-pituitary system===
 
===Hypothalamo-pituitary system===
TRH acts as a [[Releasing-hormone|releasing hormone]] that is formed by [[Hypothalamus|hypothalamic]] [[Neuron|neurons]]. It is conveyed via the [[Portal vessel|portal vessel system]] that connects hypothalamus and pituitary gland. In the pituitary it stimulates after being bound to TRHR1-[[Receptor|receptors]] in the contex of the [[Thyrotropic feedback control|Thyrotropic feedback control]] secretion of [[TSH]].
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TRH acts as a [[Releasing-hormone|releasing hormone]] that is formed by [[Hypothalamus|hypothalamic]] [[Neuron|neurons]]. It is conveyed via the [[Portal vessel|portal vessel system]] that connects hypothalamus and pituitary gland. In the pituitary it stimulates secretion of [[TSH]] after being bound to TRHR1-[[Receptor|receptors]] in the context of the [[Thyrotropic feedback control|thyrotropic feedback control]].
  
Via [[G-Protein|G-proteins]] it a delivers a [[Setpoint|setpoint]] for the [[Feedback control|feedback control]]. Additionaly, formation of TRH is inhibited in the form of [[Degenerative feedback|degenerative feedback]] by [[Thyroid hormones|thyroid hormones]].
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Via [[G-Protein|G-proteins]] it delivers a [[Setpoint|setpoint]] for the [[Feedback control|feedback control]]. Additionaly, formation of TRH is inhibited in the form of [[Degenerative feedback|degenerative feedback]] by [[Thyroid hormones|thyroid hormones]].
  
 
[[Hormone]]s and [[Transmitter]]s that are apt to influence TRH secretion are:
 
[[Hormone]]s and [[Transmitter]]s that are apt to influence TRH secretion are:
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===Gastrointestinal tract===
 
===Gastrointestinal tract===
In the [[Gastrointestinal tract|gastrointestinal tract] TRH has multiple effects, particularly on motility of [[Stomach|stomach]] and [[Intestine|intestine]] and on secretion of [[Insulin]] and [[Pancreas|pancreatic]] enzymes.
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In the [[Gastrointestinal tract|gastrointestinal tract]] TRH has multiple effects, particularly on motility of [[Stomach|stomach]] and [[Intestine|intestine]] and on secretion of [[Insulin]] and [[Pancreas|pancreatic]] enzymes.
 
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===Contextual isolation===
 
===Contextual isolation===
In peripheral blood plasma TRH is found in negligibly low concentration. Its several sites of action are contextually isolated by [[Blood-brain-barrier|blood-brain-barrier]] or the concentration gradient at the end of the [[Portal vessel|portal vessel system]] between hypothalamus and pituitary and in gastrointestinal tract, respectively. Thus, interactions among its different functions are prevented.
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In peripheral blood plasma TRH is found in negligibly low concentration. Its several sites of action are contextually isolated by [[Blood-brain-barrier|blood-brain-barrier]] or the concentration gradient at the end of the [[Portal vessel|portal vessel systems]] that are found both between hypothalamus and pituitary and in gastrointestinal tract, respectively. Thus, interactions among the different functions of TRH are prevented.
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==Clinical significane==
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As TRH is found in blood plasma in low concentration only and as this concentration is unrelated to the respective function state of the organism TRH is usually not determined in plasma. In contrast, a [[TRH-test]] is useful to identify certain disorders of [[Thyrotropic feedback control|thyrotropic feedback control]]. It is also used in [[Combined pituitary test|combined pituitary tests]].
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[[de:Thyrotropin Releasing Hormone]]

Latest revision as of 10:05, 1 April 2014

Synonym: TRH
German: Thyrotropin Releasing Hormone


1 Definition

Thyrotropin releasing hormone (TRH) is a signalling substance that is produced in several organ systems. There it plays an important role in their respective systeomics.

2 Composition

The Tripeptide TRH (pyroGlu-His-ProNH2) has a molecular weight of 362. Its structure has been first described in 1962.

3 Physiology

3.1 Hypothalamo-pituitary system

TRH acts as a releasing hormone that is formed by hypothalamic neurons. It is conveyed via the portal vessel system that connects hypothalamus and pituitary gland. In the pituitary it stimulates secretion of TSH after being bound to TRHR1-receptors in the context of the thyrotropic feedback control.

Via G-proteins it delivers a setpoint for the feedback control. Additionaly, formation of TRH is inhibited in the form of degenerative feedback by thyroid hormones.

Hormones and Transmitters that are apt to influence TRH secretion are:

3.2 Central nervous system

TRH can be found in several areas of central nervous system. More than 2/3 of this central fraction are to be found outside the zone that governs thyrotropic feedback control. Being bound to TRHR1- and TRHR2-recetpors TRH acts here as neurotransmitter or neuromodulator. It plays a central role in body temperature control, in the limbic system, in learning, in sleep, in processing of pain and in sensoric perception.

3.3 Gastrointestinal tract

In the gastrointestinal tract TRH has multiple effects, particularly on motility of stomach and intestine and on secretion of Insulin and pancreatic enzymes.

3.4 Contextual isolation

In peripheral blood plasma TRH is found in negligibly low concentration. Its several sites of action are contextually isolated by blood-brain-barrier or the concentration gradient at the end of the portal vessel systems that are found both between hypothalamus and pituitary and in gastrointestinal tract, respectively. Thus, interactions among the different functions of TRH are prevented.

4 Clinical significane

As TRH is found in blood plasma in low concentration only and as this concentration is unrelated to the respective function state of the organism TRH is usually not determined in plasma. In contrast, a TRH-test is useful to identify certain disorders of thyrotropic feedback control. It is also used in combined pituitary tests.

This page was last edited on 1 April 2014, at 10:05.

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