thyroxine is controlled by what type of feedback?

Thyroxine levels in the body are controlled by a negative feedback mechanism via the hypothalamic–pituitary–thyroid (HPT) axis.

Core idea

• When blood levels of thyroxine (T4, and T3) fall, the hypothalamus releases TRH, which stimulates the pituitary to secrete TSH, causing the thyroid gland to make and release more thyroxine.

• When thyroxine levels rise sufficiently, these hormones inhibit further release of TRH and TSH, reducing stimulation of the thyroid and bringing thyroxine back down, which is classic negative feedback.

Quick Scoop

• Type of feedback: Negative feedback control loop.

• Main pathway: Hypothalamus (TRH) → Pituitary (TSH) → Thyroid (T4/T3), with T4/T3 feeding back to both hypothalamus and pituitary to reduce TRH and TSH.

• Purpose: Keeps thyroid hormone levels within a narrow, stable range to maintain metabolic homeostasis.

TL;DR: Thyroxine is controlled by a negative feedback mechanism operating through the hypothalamic–pituitary–thyroid axis.