Transcript TSH Thyroid Stimulating Hormone Thyotropin

TSH
Thyroid Stimulating
Hormone
Thyotropin
Robert Power
How is it produced
It is produced when the hypothalamus releases the tripeptide TRH (thyrotropinreleasing hormone)
TRH travels through the pituitary portal circulation binds to TSH and prolactin
secreting cells in the pituitary gland which causes the pituitary gland to release
TSH
TSH then causes the thyroid gland to make T3 triiodothyronine or T4 thyroxine
Somatostatin decreases or inhibits the release of TSH
When T3 and T4 levels are high TSH is decreased when T3 and T4 are low TSH
is increased.
Thyroid releasing hormone
Two types TRH1 and TRH2 both of which are G protein coupled receptors.
Binding of TRH to its receptor causes a PLC mediated signaling cascade.
This causes TSH secretion and transcription and post translational glycosylation.
Biochemical traits
TSH has a half life of about an hour
It is a member of the glycoprotein hormone which consists of two subunits
alpha subunit which is encoded by the CGA gene
Unique Beta chain encoded by the TSHB gene which is on chromosome 1p13 and
contains 3 exons the first off which is non-coding.
TSH is pulsatile with peak excretion being between midnight and 4am.
Importance of TSH
Detect whether the thyroid gland is working properly such as hypothyroidism or
hyperthyroidism.
Controls the thyroid gland which controls many processes of the body.
It controls the metabolism of every tissue in the body
Normal blood values
Serum thyrotropin TSH .5-5 uU/ml
TRH stimulation test peak TSH 9-30 ulU/ml at 20-30 min
Serum thyroxine T4 4.6-12 ug/dl
Serum triiodothyronine T3 80-180ng/dl
Hypothyroidism underactive
thyroid
Hashimotos thyroiditis
Hyperthyroidism, overactive thyroid, goiters, Graves
disease
Works cited
http://images.medicinenet.com/images/slideshow/hyperthyroidism_s11_symptoms
.jpg
http://www.news-medical.net/health/Hyperthyroidism-Diagnosis.aspx
http://themedicalbiochemistrypage.org/peptide-hormones.php#tsh