Hormonal
Type 2 deiodinase (D2) and Type 3 deiodinase (D3) locally regulate thyroid hormone signaling within specific tissues independently of serum thyroid hormone concentrations.
Understanding that thyroid hormone action is locally controlled explains why standard blood tests might not reflect how you feel. Tissues like the brain, heart, and fat have their own local enzymes (D2 and D3) that activate or deactivate thyroid hormone. This means systemic blood levels are not the only factor determining metabolic rate or energy expenditure at the cellular level.
The activating deiodinase (D2) and the inactivating deiodinase (D3) can locally increase or decrease thyroid hormone signaling in a tissue- and temporal-specific fashion, independent of changes in thyroid hormone serum concentrations.
Why this rating
This is a comprehensive review of cellular and molecular mechanisms supported by extensive citations of transgenic models and kinetic studies.
Source
Cellular and Molecular Basis of Deiodinase-Regulated Thyroid Hormone Signaling1
Balázs Gereben et al. · Endocrine Reviews · 2008
DOI 10.1210/er.2008-0019
More from this paper
- Type 2 deiodinase (D2) is retained in the endoplasmic reticulum (ER), allowing locally generated T3 to have prolonged access to nuclear thyroid hormone receptors compared to T3 entering from the plasma.Strong
- Deiodinase activity is regulated by a variety of endogenous signaling molecules and xenobiotics, including hypoxia-inducible factor-1, growth factors, and bile acids.Good
Related findings · Hormonal
- Initial treatment for type 2 diabetes should be a combination of metformin and either an SGLT-2 inhibitor or a GLP-1 receptor agonist to achieve cardiorenal protection, rather than monotherapy or older agents like sulfonylureas.Strong
- For patients with specific monogenic obesity syndromes (leptin deficiency, POMC/PCSK1/LEPR mutations), targeted pharmacotherapy (recombinant leptin or setmelanotide) is highly effective and should be prioritized, unlike in polygenic obesity.Strong
- Continued weekly administration of 2.4 mg subcutaneous semaglutide prevents weight regain and promotes further weight loss in adults with overweight or obesity, whereas switching to placebo results in significant weight regain.Strong
This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →