The main difference between thyroglobulin and antithyroglobulin is that thyroglobulin is a dimeric glycoprotein follicular cells of the thyroid gland produce and is used entirely within the thyroid gland, whereas antithyroglobulin is the antibody produced against thyroglobulin protein.
Thyroglobulin and antithyroglobulin are two types of proteins that are important for the detection of problems in the thyroid gland.
Key Areas Covered
1. What is Thyroglobulin
– Definition, Structure, Function
2. What is Antithyroglobulin
– Definition, Structure, Function
3. Similarities Between Thyroglobulin and Antithyroglobulin
– Outline of Common Features
4. Difference Between Thyroglobulin and Antithyroglobulin
– Comparison of Key Differences
Key Terms
Antithyroglobulin, Thyroglobulin
What is Thyroglobulin
Thyroglobulin (Tg) is a dimeric protein produced by the follicular cells of the thyroid gland. It is also entirely used by the thyroid gland. The secretion and accumulation of thyroglobulin occur inside the extracellular compartment of the thyroid follicles. Half of the proteins in the thyroid gland are thyroglobulin. In humans, thyroglobulin is a homodimer, and each subunit of it contains 2768 amino acids. In vertebrates, thyroglobulin is a precursor to thyroid hormones. Each thyroglobulin molecule consists of 100-120 tyrosine residues. Tyrosine molecules combine with the iodine and undergo subsequent cleavage of the tyrosine hormone. Each thyroglobulin forms around 10 thyroid hormone molecules.
Figure 1: Thyroid Hormone Synthesis
Furthermore, the main function of thyroglobulin is to serve as the precursor of thyroid hormones: thyroxine (T4) and triiodothyronine (T3). In thyroid follicles, the inactive form of thyroid hormones and iodine is stored within the follicular lumen. Moreover, newly synthesized thyroid hormones are attached to the thyroglobulin and comprise a colloid within the follicle. Meanwhile, thyroid stimulating hormone stimulates the colloid to endocytose from the follicular lumen into the surrounding thyroid follicular epithelial cells. Thyroglobulin is released from T3 and T4 by subsequent cleavage with protease.
What are Antithyroglobulin
Antithyroglobulin is an antibody produced against thyroglobulin, the precursor protein of the thyroid hormones. Antithyroglobulin can damage the thyroid gland and affects its function. However, the testing of antithyroglobulin antibodies in the blood is useful for diagnosing thyroid disorders as well as other disorders in the body. Antithyroglobulin antibodies increase in Hashimoto thyroiditis, an autoimmune thyroid disease. The other disease conditions with increased antithyroglobulin antibodies are Graves disease (overactivity of the thyroid), rheumatoid arthritis, hypothyroidism (under activity of the thyroid), thyroid cancer, lupus, autoimmune hemolytic anemia, and Sjogren syndrome.
Figure 2: Hyperthyroidism
Moreover, antithyroid antibodies are another name for antithyroglobulin antibodies. Normal results of the antithyroglobulin test should be negative when tested for antithyroglobulin antibodies. Positive test results indicate the presence of disease conditions in the thyroid gland.
Similarities Between Thyroglobulin and Antithyroglobulin
- Thyroglobulin and antithyroglobulin are two types of proteins.
- They are important for the detection of thyroid problems.
Difference Between Thyroglobulin and Antithyroglobulin
Definition
Thyroglobulin refers to a protein present in the thyroid gland, from which thyroid hormones are synthesized, while antithyroglobulin refers to an antibody directed against thyroglobulin, which is a key protein in the thyroid gland essential to the production of thyroid hormones.
Occurrence
Thyroglobulin occurs in the thyroid gland, while antithyroglobulin occurs in the bloodstream.
Function
Moreover, thyroglobulin is the precursor for the production of thyroid hormones, while antithyroglobulin can damage the thyroid gland affecting its function.
Conclusion
In brief, thyroglobulin and antithyroglobulin are two types of proteins occurring in the thyroid gland. Thyroglobulin is a glycoprotein occurring in the thyroid gland. It is also a precursor for the production of thyroid hormones in the thyroid gland. In comparison, antithyroglobulin is an antibody formed against thyroglobulin protein. However, it can affect the function of the thyroid gland damaging the thyroid gland. Therefore, the main difference between thyroglobulin and antithyroglobulin is their function.
References:
- “Thyroglobulin.” Wikipedia. Wikimedia Foundation.
- “Medical definition of antithyroglobulin.” RxList.
Image Courtesy:
- “Thyroid hormone synthesis” By Mikael Häggström – Own work (CC0) via Commons Wikimedia
- “Hyperthyroidism (2)” By KGH – Own Work (CC-BY SA 3.0) via Commons Wikimedia
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