TSH Functional Assay

Thyroid-stimulating hormone (TSH), secreted by the pituitary gland, is the most important regulator of thyroid function. TSH is involved in a range of endocrine processes, including thyroid iodine uptake, globulin iodination, reuptake, and thyroid cell growth. It can be said that the cellular processes the thyroid hormone is involved are all regulated by TSH. Based on the powerful platform, Creative Biolabs delivers the most relevant and robust TSH functional assay and related services according to your specific demands.

How does TSH Function?

TSH is a glycoprotein hormone composed of a non-covalent linkage of an alpha subunit to a beta subunit, wherein the α subunit is structurally similar to follitropin and luteinizing hormone, whereas the unique β subunit confers its biological and immunological specificity. The secretion and release of TSH are regulated by the thyrotropin-releasing hormone (TRH). Low levels of circulating thyroid hormones induce the secretion of released TRH, which in turn stimulates the expression and presentation of TSH, TSH then interacts with specific receptors on the surface of thyroid cells (TSHR) to promote the secretion of the metabolically active thyroid hormones T3 and T4, while T4 and T3 inhibit TSH production through a typical negative feedback mechanism. The regulation and stimulation of cell behavior by TSH are generally carried out through the Gs/cAMP pathway. In addition, some studies also proved that Gq and Ca²⁺ also played a role in this process.

Fig 1. Structure prediction of TSH beta subunit, obtained from AlphaFold. (Uniprot ID: B3DJU0)

TSH Functional Assay

TSH function testing is an important part of laboratory thyroid function characterization, which can be performed in a variety of ways. The ability of TSH to bind to its receptors is usually quantified by immunoglobulin binding assays, other methods such as competitive protein binding, radio-immunoassays, and radioreceptor assays, are also commonly used. In addition, non-radioactive immunological methods, such as enzyme immunoassay, enzyme-linked immunosorbent assay, immunofluorescence, and immune-chemiluminescence, are also extensively applied for qualitative or quantitative assessment of TSH function.

Fig 2. Detection of TSH and TRAb function using competitive ligands. (Napolitano, et al., 2021)

Our TSH Functional Assay Service

Abnormal expression of TSH or self-resistance to TSH can lead to multiple endocrine diseases or metabolic disorders. At Creative Biolabs, we can achieve professional and efficient TSH functional assays by using validated cell lines stably expressing TSHR or TSH and determining the biological activity of TSH by measuring the downstream cell products. In addition, it is also feasible to directly measure the content and function of TSH by various protein competition assays or immunological means.

If we can improve your project in any way or you have any further demands, please don't hesitate to contact us.

Reference

1. Napolitano, G.; et al. Non-conventional clinical uses of TSH receptor antibodies: the case of chronic autoimmune thyroiditis. Frontiers in Endocrinology. 2021, 12: 769084.