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How does negative feedback regulate thyroid hormone production?

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Diagram showing the locations of major human endocrine glands in male and female bodies, including pineal gland, hypothalamus, pituitary gland, parathyroid glands, thyroid gland, thymus, adrenal glands, pancreas, kidneys, testes, and ovaries. — Endocrine system The glands of the human endocrine system.

The thyroid gland operates within the hypothalamic-pituitary-thyroid axis, a negative feedback control system that maintains hormone levels within a narrow range.12

The process is regulated as follows:

Stimulation: The hypothalamus releases thyrotropin-releasing hormone, which triggers the anterior pituitary gland to secrete thyrotropin. Thyrotropin then stimulates the thyroid gland to produce and release thyroxine and triiodothyronine.134
Inhibition: Once thyroid hormone concentrations rise, they act on the pituitary gland and hypothalamus to inhibit the further production and secretion of both thyrotropin and thyrotropin-releasing hormone.14
Correction: If thyroid hormone levels drop, the reduction in negative feedback allows for increased secretion of thyrotropin, which stimulates the thyroid to restore hormone levels to normal.14

This mechanism ensures that the body maintains appropriate metabolic balance; disruptions to this feedback loop can lead to conditions such as hypothyroidism or hyperthyroidism.14