Thyrotropin subunit beta

approved

Also known as: Thyroid-stimulating hormone subunit beta, Thyrotropin beta chain, TSHB, P01222

**Mechanism of Action** Thyrotropin subunit beta (TSHB) is the β-chain of thyroid-stimulating hormone (TSH), a heterodimeric glycoprotein essential for hypothalamic-pituitary-thyroid axis regulation. TSHB non-covalently associates with the α-subunit (common to LH, FSH, hCG) to form bioactive TSH. TSH binds to the TSH receptor (TSHR) on thyroid follicular cells, activating Gs-protein/cAMP and Gq/11 pathways. This stimulates thyroid hormone (T3/T4) synthesis and secretion, iodide uptake, thyroglobulin production, and thyroid cell proliferation. TSHB is exclusively expressed in pituitary thyrotrophs, and its secretion is regulated by thyrotropin-releasing hormone (TRH) and negative feedback from thyroid hormones. **Key Research Findings** TSHB mutations cause congenital hypothyroidism (CH) with autosomal recessive inheritance, characterized by low TSH but normal α-subunit levels. Over 20 pathogenic variants (e.g., missense, frameshift) have been identified, impairing subunit dimerization or receptor binding. TSHB is also a biomarker for pituitary function; suppressed levels indicate hyperthyroidism or central hypothyroidism. Animal models show TSHB knockout mice exhibit hypothyroidism, growth retardation, and thyroid atrophy. Approved recombinant human TSH (rhTSH) uses the α-subunit with TSHB to stimulate radioiodine uptake in thyroid cancer monitoring. **Clinical Relevance** TSHB is a validated therapeutic target for thyroid disorders. Recombinant TSH (Thyrogen®) is FDA-approved for adjunctive use in thyroid cancer follow-up, enabling radioiodine imaging without hormone withdrawal. TSHB gene testing aids diagnosis of CH in neonates with ambiguous TSH levels. TSHB measurement differentiates primary (high TSH) from central (low TSH) hypothyroidism. No direct TSHB-based therapies exist for hyperthyroidism, but TSHR antagonists are in development. For research purposes only — not medical advice.

Key data

Category
Hormonal & Endocrine
Sequence
MTALFLMSMLFGLTCGQAMSFCIPTEYTMHIERRECAYCLTINTTICAGYCMTRDINGKLFLPKYALSQDVCTYRDFIYRTVEIPGCPLHVAPYFSYPVALSCKCGKCNTDYSDCIHEAIKTNYCTKPQKSYLVGFSV
Molecular weight
15639 g/mol
Research status
approved
References
9
Tags
uniprot, 3d-structure, alternative-splicing, congenital-hypothyroidism, direct-protein-sequencing, disease-variant, disulfide-bond, glycoprotein, hormone, pharmaceutical, proteomics-identification, reference-proteome

Mechanism of action

Indispensable for the control of thyroid structure and metabolism

Research & studies

Effect of food intake on biomarkers measured by the Proseek Multiplex Metabolism panel
Clinical physiology and functional imaging · 2026 · PubMed
Maternal Thyroid Hormone Programs Cardiovascular Functions in the Offspring
Thyroid : official journal of the American Thyroid Association · 2021 · PubMed

Maternal T3 treatment in either half of pregnancy did not affect postnatal growth or serum thyroxine levels.; Heart weight was significantly increased in adult wild-type offspring exposed to maternal T3 in either half of pregnancy, but TRα1 mutant males were protected.; Heart rate was significantly increased only in male mice exposed to elevated maternal T3 during the second half of pregnancy.; Serum selenium levels were reduced by maternal T3 treatment in wild-type offspring of both genders.

Gene clusters related to metamorphosis in Solea senegalensis are highly conserved
Comparative biochemistry and physiology. Part D, Genomics & proteomics · 2020 · PubMed

Three BAC clones (trhr1a, trhr2, thr) showed double signals, indicating genomic duplication from TS-WGD.; The tsh BAC clone was highly conserved, with its genes located on a single chromosome across all studied species.; Micro-synteny analysis revealed most candidate genes are in conserved genomic surroundings.; Cynoglossus semilaevis is the nearest species to S. senegalensis, while Danio rerio is the most distant.

Deep mitochondrial DNA phylogeographic divergence in the threatened aoudad Ammotragus lervia (Bovidae, Caprini)
Gene · 2020 · PubMed
Brain Transcriptome Profiling Analysis of Nile Tilapia (Oreochromis niloticus) Under Long-Term Hypersaline Stress
Frontiers in physiology · 2018 · PubMed
3-Iodothyronamine Decreases Expression of Genes Involved in Iodide Metabolism in Mouse Thyroids and Inhibits Iodide Uptake in PCCL3 Thyrocytes
Thyroid : official journal of the American Thyroid Association · 2017 · PubMed
Timing of metamorphosis and the onset of the negative feedback loop between the thyroid gland and the pituitary is controlled by type II iodothyronine deiodinase in Xenopus laevis
Proceedings of the National Academy of Sciences of the United States of America · 2001 · PubMed

Frequently asked questions

What is Thyrotropin subunit beta?

**Mechanism of Action** Thyrotropin subunit beta (TSHB) is the β-chain of thyroid-stimulating hormone (TSH), a heterodimeric glycoprotein essential for hypothalamic-pituitary-thyroid axis regulation. TSHB non-covalently associates with the α-subunit (common to LH, FSH, hCG) to form bioactive TSH. TSH binds to the TSH r

How does Thyrotropin subunit beta work?

Indispensable for the control of thyroid structure and metabolism

What is the research status of Thyrotropin subunit beta?

Thyrotropin subunit beta is currently classified as approved, with 9 research references on record. This is for research purposes only and is not medical advice.

What is the molecular weight of Thyrotropin subunit beta?

Thyrotropin subunit beta has a molecular weight of approximately 15639 g/mol.

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