Description
Introduction: Thyroid-stimulating hormone (also known as TSH or thyrotropin) is a peptide hormone synthesized and secreted by thyrotrope cells in the anterior pituitary gland which regulates the endocrine function of the thyroid gland. TSH stimulates the thyroid gland to secrete the hormones thyroxine (T4) and triiodothyronine (T3).TSH production is controlled by thyrotropin-releasing hormone (TRH), which is manufactured in the hypothalamus and transported to the anterior pituitary gland via the superior hypophyseal artery, where it increases TSH production and release. Somatostatin is also produced by the hypothalamus, and has an opposite effect on the pituitary production of TSH, decreasing or inhibiting its release. The level of thyroid hormones (T3 and T4) in the blood have an effect on the pituitary release of TSH; when the levels of T3 and T4 are low, the production of TSH is increased, and conversely, when levels of T3 and T4 are high, then TSH production is decreased. This effect creates a regulatory negative feedback loop.
Principle of the Assay: This assay employs the direct competitive inhibition enzyme immunoassay technique. An antibody specific for TSH has been pre-coated onto a microplate. Add TSH (Standards or samples) to the well, and then add Biotin conjugated TSH. A competitive inhibition reaction is launched between TSH (Standards or samples) and Biotin conjugated TSH with the TSH antibody. Then add the HRP-avidin to each well. The substrate solutions are added to the wells, respectively. And the color develops in opposite to the amount of TSH bound in the initial step. The color development is stopped and the intensity of the color is measured