THYROTROPIN (TSH)
Thyroid-stimulating hormone (also known as TSH or thyrotropin) is a peptide hormone synthesized and secreted by thyrotrope cells in the anterior pituitary gland, which regulates the endocrine function of the thyroid gland.It is a glycoprotein weighing about 28000 kd.[11]
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Functions of the TSH.
1.Stimulates the growth and proliferation of thyroid gland by-
2.Increases the secretory activity of the thyroid cells.
Regulation of TSH-
TSH test
A TSH test measures the amount of thyroid stimulating hormone (TSH) in your blood. TSH is produced by the pituitary gland and tells the thyroid gland to make and release the hormones thyroxine (T4) and triiodothyronine (T3).
Normal values are 0.4 - 4.0 mIU/L (milli-international units per liter).
However, those without signs or symptoms of an underactive thyroid who have a TSH value over 2.0 mIU/L but normal T4 levels may develop hypothyroidism in the future. This is called subclinical hypothyroidism (mildly underactive thyroid) or early-stage hypothyroidism. Anyone with a TSH value above this level should be followed very closely by a doctor.
If you are being treated for a thyroid disorder, your TSH level should be between 0.5 and 3.0 mIU/L.
Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
Hyposecretion:-
It leads to thyroid atrophy.
Hypersecretion:-
It leads to increased B.M.R, B.P and Heart rate.
Loss of weight.
Symptoms of Grave's disease. [12]
1.Stimulates the growth and proliferation of thyroid gland by-
- Increases the size and secretary activity of the thyroid cells.
- Increased rate of division of thyroid cells
- Conversion of cuboidal follicular cells to columnar for engulfing colloid.
2.Increases the secretory activity of the thyroid cells.
- Increases proteolysis of thryoglobulin stored in follicles
- Increased activity of the iodine pump
- Increases iodination of tyrosine.[B2]
Regulation of TSH-
- Controlled by th TRH secreted by the hypothalamus.
- Acts through PIP2 secondary messanger system
- It gets stimulated generally by cold or emotional stimuli.
- This secretion is controlled ya a negative feedback mechanism.
TSH test
A TSH test measures the amount of thyroid stimulating hormone (TSH) in your blood. TSH is produced by the pituitary gland and tells the thyroid gland to make and release the hormones thyroxine (T4) and triiodothyronine (T3).
Normal values are 0.4 - 4.0 mIU/L (milli-international units per liter).
However, those without signs or symptoms of an underactive thyroid who have a TSH value over 2.0 mIU/L but normal T4 levels may develop hypothyroidism in the future. This is called subclinical hypothyroidism (mildly underactive thyroid) or early-stage hypothyroidism. Anyone with a TSH value above this level should be followed very closely by a doctor.
If you are being treated for a thyroid disorder, your TSH level should be between 0.5 and 3.0 mIU/L.
Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
Hyposecretion:-
It leads to thyroid atrophy.
Hypersecretion:-
It leads to increased B.M.R, B.P and Heart rate.
Loss of weight.
Symptoms of Grave's disease. [12]