title: The autodecomposition of radiolabeled human growth hormone.
abstract: Human growth hormone (hGH) was radiolabeled with 125I, using a gentle lactoperoxidase technique. The stability and decomposition products of this tracer were studied by frequent periodic analysis by Sephadex G-100 chromatography on a long column. Monomeric 125I-hGH showed an exponential decline, with a half-life of 61 days. The main radioactive degradation product was iodide, which appeared with a fractional appearance rate of 0.01136 per day. Secondary degradation products were a series of radioactive oligomers of hGH, which appeared with an overall fractional rate of 0.00525 per day. The kinetic data obtained should provide guidelines for the shelf-life and repurification schedule of radioiodinated polypeptides.
mesh_terms: D004355:Drug Stability; D013006:Growth Hormone / Q000031:analogs & derivatives*; D006801:Humans; D007457:Iodine Radioisotopes; D011854:Radiochemistry; D013997:Time Factors
chemical_list: D007457:Iodine Radioisotopes; C035648:somatotropin, iodinated; D013006:Growth Hormone