Thyroid Hormone Function and Disorders

The thyroid gland produces the hormones thyroxine (T4) and triiodothyronine (T3), which are central regulators of basal metabolic rate, thermogenesis, cardiac function and neurodevelopment. Production is controlled by the hypothalamic–pituitary–thyroid axis, in which thyroid-stimulating hormone (TSH) from the pituitary drives hormone synthesis and secretion. Peripheral conversion of T4 to the active T3 form is mediated by deiodinase enzymes, ensuring tissue-specific regulation. Dysregulation of this system gives rise to disorders ranging from overt hypothyroidism—marked by bradycardia, weight gain and fatigue—to hyperthyroidism, which presents with tachycardia, weight loss and heat intolerance. Autoimmune processes underlie the most common thyroid diseases, including Graves’ disease and Hashimoto’s thyroiditis, in which aberrant antibody production disrupts gland function. Subclinical variations in thyroid function have gained recognition for contributing to cardiovascular risk, neurocognitive impairment and metabolic disturbances. Treatment strategies span hormone replacement, antithyroid drugs and, in refractory cases, surgery or radioiodine therapy. Despite widespread screening, individual variations in hormone transport, metabolism and receptor sensitivity continue to challenge optimal management and point to the need for personalised approaches.

Research from Nature Portfolio

Large-scale genome-wide association analyses have identified over one hundred genetic loci linked to thyroid hormone levels and disease susceptibility. Functional follow-up has revealed novel players in hormone transport and metabolism, notably the transporter SLC17A4 and the deiodinase-like enzyme AADAT, which modulate cellular uptake and conversion of T4 to T3. A composite genetic risk score incorporating these variants correlates with both overt and subclinical thyroid dysfunction, as well as clinical complications. These insights not only deepen understanding of the genetic architecture underlying hormone homeostasis but also highlight potential molecular targets for next-generation therapies aimed at restoring euthyroidism in diverse patient groups.

Research from all publishers

Meta-analytic evidence has established a strong association between obesity and thyroid autoimmunity, with excess adiposity increasing the risk of both overt and subclinical hypothyroidism as well as positive thyroid peroxidase antibody status. These findings underscore the bidirectional interplay between metabolic health and thyroid function, suggesting that weight management may mitigate thyroid-related immune activation. Concurrently, advances in in vitro screening methods and adverse outcome pathway frameworks have enabled high-throughput evaluation of environmental chemicals that interfere with thyroid hormone signalling. Such approaches aim to predict developmental neurotoxicity and inform regulatory decisions without reliance on animal testing. Together, these studies emphasise the multifactorial nature of thyroid disorders, integrating lifestyle, environmental and molecular determinants, and pave the way for improved public health interventions and personalised risk assessment.

Thyroid Hormone Function and Disorders publication trend

The graph below shows the total number of articles in thyroid hormone function and disorders across all publications each year (not limited to Nature Index journals).

Technical terms

Thyroxine (T4): The main prohormone released by the thyroid gland, converted peripherally into the active hormone T3.

Triiodothyronine (T3): The biologically active thyroid hormone that binds nuclear receptors to regulate gene transcription.

Deiodinases: Enzymes that activate or inactivate thyroid hormones by removing iodine atoms, controlling tissue-specific hormone availability.

Hypothalamic–pituitary–thyroid axis: The regulatory feedback loop in which hypothalamic TRH stimulates pituitary TSH release, which in turn drives thyroid hormone synthesis.

Subclinical hypothyroidism: A state of elevated TSH with normal T4/T3 levels, often asymptomatic but associated with increased cardiovascular risk.

References

1. Genome-wide analyses identify a role for SLC17A4 and AADAT in thyroid hormone regulation. Nature Communications (2018).
2. The Impact of Obesity on Thyroid Autoimmunity and Dysfunction: A Systematic Review and Meta-Analysis. Frontiers in Immunology (2019).
3. Evaluating Chemicals for Thyroid Disruption: Opportunities and Challenges with in Vitro Testing and Adverse Outcome Pathway Approaches. Environmental Health Perspectives (2019).