Thyroid hormones are involved in many metabolic functions, including maintain temperature homeostasis.

When body temperature drops, the hypothalamus secretes thyroid-releasing hormone (TRH).

TRH stimulates the anterior pituitary to secrete thyroid-stimulating hormone (TSH).

TSH then stimulates the thyroid gland to synthesize the thyroid hormones T₃ and T₄.

T₃ and T₄ in turn exert negative feedback on the hypothalamus and anterior pituitary and inhibit release of TRH and TSH.