Serum parathyroid hormone

Parathyroid hormone (parathyroid hormone) is a basic single-chain polypeptide hormone secreted by parathyroid main cells. Referred to as PTH. Parathyroid hormone is composed of 84 amino acids. Its main function is to regulate the metabolism of calcium and phosphorus in vertebrates, which promotes the increase of blood calcium levels and the decrease of blood phosphorus levels. The first precursor substance of PTH is first synthesized in the main cells of the parathyroid gland, called proprothyroid hormone, containing 115 amino acids. Later, this precursor substance is cleaved into a second precursor substance containing 90 amino acids in the shape of a parathyroid hormone. Paraprohormone, which in turn is cleaved in the cell to a peptide containing 84 amino acids, or PTH. The concentration of PTH in normal human plasma is about 1 ng / ml. The main role of parathyroid hormone is to increase the activity and number of osteoclasts, increase blood calcium; inhibit the absorption of phosphorus by renal tubules, and promote the absorption of calcium and phosphorus in the intestine. Clinically, radioimmunoassay and immunochemical fluorescence are commonly used for determination.