Which hormone from the anterior pituitary stimulates the production of thyroid hormones?

• A. FSH
• B. LH
• C. TSH
• D. ACTH

Answer: (C)

Thyroid-stimulating hormone from the anterior pituitary is the signal that triggers thyroid hormone production. It is released in response to releasing hormone from the hypothalamus and binds to receptors on thyroid follicular cells, promoting the synthesis and release of the thyroid hormones T3 and T4. This stimulation includes increasing iodide uptake and the activity of the enzymes needed to make thyroglobulin and thyroid hormones. The result is more thyroid hormone in circulation, which then feeds back negatively to suppress further release of TRH and TSH.

Other hormones listed act on different target organs: FSH and LH regulate the gonads, while ACTH stimulates the adrenal cortex to produce cortisol. They do not directly drive thyroid hormone production.