Role of iodine in thyroid physiology

Area of Science:

• Endocrinology
• Molecular Biology
• Public Health

Background:

• Iodine is a crucial trace element for synthesizing thyroid hormones thyroxine (T4) and triiodothyronine (T3).
• The thyroid gland utilizes a specific iodide cycle involving transport, oxidation, and coupling within follicular cells.
• Adequate iodine levels are vital for normal thyroid function and overall health.

Purpose of the Study:

• To elucidate the mechanisms of iodine transport and utilization in thyroid hormone synthesis.
• To highlight the physiological and clinical consequences of iodine deficiency and excess.
• To underscore the public health significance of iodine in preventing cognitive impairment.

Main Methods:

• Review of the molecular mechanisms of iodide transport, including the sodium/iodide symporter (NIS) and pendrin.
• Analysis of thyroid autoregulation mechanisms like the Wolff-Chaikoff effect and Jöd-Basedow phenomenon.
• Examination of population studies on iodine deficiency prevalence and its health impacts.

Main Results:

• Iodide uptake is mediated by NIS, while pendrin facilitates its efflux into the follicular lumen.
• Inhibitors of NIS, such as perchlorate, can disrupt iodide uptake.
• Iodine excess or deficiency can lead to thyroid dysfunction, including the Wolff-Chaikoff effect and Jöd-Basedow phenomenon.

Conclusions:

• Iodine is indispensable for thyroid hormone synthesis and function.
• Iodine deficiency is a significant global health issue, linked to preventable intellectual disability.
• Understanding iodine's role in thyroid physiology is critical for clinical applications and public health interventions.