Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
Britannica Sources used in this answer

What role does thyrotropin play when thyroid hormone levels decrease?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
A labeled diagram highlights the periodic table entry for iodine, atomic number 53, symbol I, atomic weight 126.90447, and electron configuration. It shows iodine as a solid halogen with an orthorhombic crystal structure and strongly acidic higher-valence oxides, using color and shape keys for classification.
iodine

When thyroid hormone levels decrease, the body utilizes a negative feedback control system to restore balance. Under normal conditions, thyroid hormones inhibit the production and secretion of thyrotropin (also known as thyroid-stimulating hormone) from the anterior pituitary gland.12

When circulating thyroid hormone concentrations fall, this inhibitory effect is reduced, leading to an increase in thyrotropin secretion. Thyrotropin then travels to the thyroid gland, where it binds to specific receptors and performs several critical functions to increase thyroid hormone levels:12

  • It stimulates the breakdown of thyroglobulin to release thyroxine and triiodothyronine into the circulation.2
  • It promotes the synthesis of additional thyroglobulin and thyroid hormone.2
  • It encourages the growth of thyroid cells.2

This process effectively increases thyroid hormone secretion, helping to restore serum concentrations to normal levels, provided the thyroid gland is not severely damaged.1