Tyrotropin

Tyrotropin is a glycoprotein hormone produced by the anterior pituitary gland. Its primary function is to stimulate the thyroid gland to produce and release thyroid hormones, namely thyroxine (T4) and triiodothyronine (T3). Tyrotropin is also known as thyroid-stimulating hormone (TSH). The release of tyrotropin is regulated by a negative feedback loop involving thyroid hormones and thyrotropin-releasing hormone (TRH) from the hypothalamus. When levels of T4 and T3 in the blood are low, TRH is released by the hypothalamus, which in turn stimulates the anterior pituitary to release tyrotropin. This increased tyrotropin then acts on the thyroid gland to boost T4 and T3 production. Conversely, when thyroid hormone levels are high, TRH and tyrotropin release are suppressed. Tyrotropin plays a crucial role in metabolism, growth, and development. Abnormal levels of tyrotropin can indicate various thyroid disorders. For example, elevated tyrotropin levels are often seen in hypothyroidism, where the thyroid gland is underactive. Conversely, suppressed tyrotropin levels can be indicative of hyperthyroidism, where the thyroid gland is overactive. Clinical measurement of tyrotropin is a common diagnostic tool for assessing thyroid function.