Peptide hormones or protein hormones are ..

Conversely, when TSH levels are low, rates of thyroid hormone synthesis and release diminish.

Regulation of hormone synthesis of ..



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Synthesis and Secretion of Thyroid Hormones

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Thyroid hormones are synthesized by mechanisms fundamentally different from what is seen in other endocrine systems.

The left diagram shows a steroid (lipid) hormone ..



Constructing Thyroid Hormones
The entire synthetic process occurs in three major steps, which are, at least in some ways, analagous to those used in the manufacture of integrated circuits (ICs):

Production and accumulation of the raw materials (in the case of ICs, a large wafer of doped silicon)
Fabrication or synthesis of the hormones on a backbone or scaffold of precursor (etching several ICs on the silicon wafer)
Release of the free hormones from the scaffold and secretion into blood (cutting individual ICs out of the larger wafer and distributing them)
The recipe for making thyroid hormones calls for two principle raw materials:

Tyrosines are provided from a large glycoprotein scaffold called thyroglobulin, which is synthesized by thyroid epithelial cells and secreted into the lumen of the follicle - colloid is essentially a pool of thyroglobulin.

This final act in thyroid hormone synthesis proceeds in the following steps:

Thyroid epithelial cells ingest colloid by endocytosis from their apical borders - that colloid contains thyroglobulin decorated with thyroid hormone.


is increased PTH protein synthesis followed by ..

Binding of TSH to receptors on thyroid epithelial cells seems to enhance all of the processes necessary for synthesis of thyroid hormones, including synthesis of the iodide transporter, thyroid peroxidase and thyroglobulin.