Sandbox Reserved 1650: Difference between revisions

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Once iodization and coupling have been performed, endocytosis of the colloid to the lysosome occurs. The TG is proteolyzed by cathepsin proteases<ref>DOI 266(30):20198-20204</ref> [a] and 7 TH are thus released from 14 mono- or di iodinated tyrosines.
Once iodization and coupling have been performed, endocytosis of the colloid to the lysosome occurs. The TG is proteolyzed by cathepsin proteases<ref>DOI 266(30):20198-20204</ref> [a] and 7 TH are thus released from 14 mono- or di iodinated tyrosines.
   
   
The hormone synthesis function of TG is thus particularly linked to its structure. Moreover, research shows that denaturation or a simple modification of its conformation prevents the formation of HT <ref>DOI 10.1016/0005-2795(73)90365-6</ref><ref>DOI 456595</ref>. [k]
The hormone synthesis function of TG is thus particularly linked to its structure. Moreover, research shows that denaturation or a simple modification of its conformation prevents the formation of TH <ref>DOI 10.1016/0005-2795(73)90365-6</ref><ref>DOI 456595</ref>. [k]
[l]
[l]


==== Control ====
==== Control ====
The synthesis of HT from TG is stimulated by thyroid stimulating hormone (TSH) secreted by the pituitary gland, a gland of the brain. When the TSH receptor is activated, glycosylations leading to the mono iodination of tyrosines promote the synthesis of T3<ref>DOI  3182849</ref><ref>DI 10.1016/S0021-9258(18)46037-1</ref>. b][c]  
The synthesis of TH from TG is stimulated by thyroid stimulating hormone (TSH) secreted by the pituitary gland, a gland of the brain. When the TSH receptor is activated, glycosylations leading to the mono iodination of tyrosines promote the synthesis of T3<ref>DOI  3182849</ref><ref>DI 10.1016/S0021-9258(18)46037-1</ref>. b][c]  
On the other hand, if the amount of hormones is too high, a negative feedback is exerted on this process while a small amount of these hormones exerts a positive feedback.
On the other hand, if the amount of hormones is too high, a negative feedback is exerted on this process while a small amount of these hormones exerts a positive feedback.


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A healthy subject has between 5 and 25 µg of TG per liter of blood. In case of thyroid dysfunction, this level may increase or decrease. For example, it decreases in the case of congenital athyreosis (insufficiency of the thyroid gland) or prior to a miscarriage due to the presence of anti-TG antibodies, but increases in the case of cancer, thyroiditis, inflammation of the thyroid or autoimmune thyroid diseases AITD (Grave's disease, Hashimoto's thyroiditis).
A healthy subject has between 5 and 25 µg of TG per liter of blood. In case of thyroid dysfunction, this level may increase or decrease. For example, it decreases in the case of congenital athyreosis (insufficiency of the thyroid gland) or prior to a miscarriage due to the presence of anti-TG antibodies, but increases in the case of cancer, thyroiditis, inflammation of the thyroid or autoimmune thyroid diseases AITD (Grave's disease, Hashimoto's thyroiditis).
   
   
In addition, a decrease in the size or capacity of the thyroid causes a decrease in the synthesis of HT by the TG, and thus a drop in the blood level of T4 and T3, which in turn causes heart disease, brain disease and abnormalities in the development of the fetus.  
In addition, a decrease in the size or capacity of the thyroid causes a decrease in the synthesis of TH by the TG, and thus a drop in the blood level of T4 and T3, which in turn causes heart disease, brain disease and abnormalities in the development of the fetus.  
   
   
TG can thus be as much a cause as a consequence of disease.
TG can thus be as much a cause as a consequence of disease.
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