Homologous Radioimmunoassay for Human Parathyroid Hormone (Residues 44–68) with Tyrosylated Peptide as Tracer

摘要: Along with the steroid hormone 1,25-dihydroxyvitamin D3 and peptide calcitonin, polypeptide parathyroid (parathyrin) (PTH) is responsible for maintaining calcium phosphorus homeostasis in vertebrates. A decrease concentration of serum followed by release 84-amino-acid PTH some its fragments from secretory granules glands into bloodstream. These peptides undergo rapid proteolytic cleavage liver kidneys to yield N- C-terminal PTH. The half-life fragment, which believed be biologically inert, about 20–40 min, whereas N-terminal fragment intact disappear much faster circulation (t 1/2 < 5 min) [1–3]. Thus, assays reflect state at time blood sampling. For diagnosis hyperparathyroidism, however, these results might misleading if secretion has temporarily been suppressed [3]. In contrast, both middle region (residues 44–68) (53–84) will give an integrated value immunoreactive (iPTH), reflecting chronic gland function