title: Preparation and properties of biologically active radioiodinated parathyroid hormone.
abstract: A constant-current microelectrolytic radioiodination method was used to label bovine parathyroid hormone (BPTH) with 125I to an overall iodination ratio of 1:1 iodide atoms per PTH molecule. Such iodinated preparations were shown to be fully active in several bioassay systems: in vitro adenylate cyclase activation in rat renal and skeletal membranes, in vitro calcium release from rat calvaria, and the in vivo hypercalcemic response in chickens. Analysis by Sephadex G-15 chromatography after enzymatic digestion showed the radioiodine to be incorporated predominantly as monoiodotyrosine. Bioassay of iodinated preparations from which uniodinated hormone had been removed by isoelectric focusing showed essentially full hormonal activity. Such methods can be used to consistently produce radioiodinated biologically active preparations of BPTH 1-84 with high specific activity (2000 Ci/mmol).
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001842:Bone and Bones / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002645:Chickens; D002855:Chromatography, Thin Layer; D006934:Hypercalcemia / Q000378:metabolism; D007457:Iodine Radioisotopes; D007525:Isoelectric Focusing; D007553:Isotope Labeling / Q000379:methods*; D007672:Kidney Cortex / Q000378:metabolism; D008297:Male; D010281:Parathyroid Hormone / Q000502:physiology; D051381:Rats
chemical_list: D007457:Iodine Radioisotopes; D010281:Parathyroid Hormone; D000262:Adenylyl Cyclases; D002118:Calcium