Thyrotropin-releasing hormone (TRH), also known as protirelin, is used in diagnostic testing to assess the function of the hypothalamic-pituitary-thyroid (HPT) axis. When administered, TRH stimulates the anterior pituitary gland to release thyroid-stimulating hormone (TSH), which in turn triggers the thyroid gland to produce and secrete thyroid hormones — T3 (triiodothyronine) and T4 (thyroxine).
These thyroid hormones are essential for regulating metabolism, cardiac function, and overall growth and development. TRH testing is commonly used to diagnose thyroid disorders and evaluate pituitary or hypothalamic dysfunction.