Thyroglobulin is responsible for the formation of which thyroid hormones?

Thyroglobulin is a large glycoprotein produced by the thyroid gland, and it plays a crucial role in the synthesis of thyroid hormones, specifically triiodothyronine (T3) and thyroxine (T4). This process begins with the uptake of iodine by the thyroid follicular cells, where it is then combined with the amino acid tyrosine, which is a component of thyroglobulin.

The iodination of tyrosine residues within thyroglobulin leads to the formation of monoiodotyrosine (MIT) and diiodotyrosine (DIT). These precursors then undergo further coupling reactions: two DIT molecules combine to form thyroxine (T4), while one MIT and one DIT come together to yield triiodothyronine (T3).

The absence of thyroglobulin would inhibit the formation of these hormones, leading to significant metabolic consequences. Therefore, understanding the role of thyroglobulin in synthesizing T3 and T4 is fundamental to comprehending thyroid function and hormonal regulation in the body.