title: [Assay of 24,25-dihydroxyvitamin D by competitive protein binding].
abstract: A competitive protein binding radioassay for 24,25-dihydroxyvitamin D in human serum has been developed, which is relatively simple and rapid. Acetonitrile is used for sample extraction and protein precipitation. column chromatography is then performed in a Sep-pak cartridge. High pressure liquid chromatography follows. The dried eluate is assayed using rat serum as the source of binding protein. Since 25-hydroxyvitamin D3 and 24,25-dihydroxyvitamin D3 are equipotent in their competitive displacement of tritiated 25-hydroxyvitamin D3 from at serum, 25-hydroxyvitamin D3 can be used as the assay standard.
mesh_terms: D015650:24,25-Dihydroxyvitamin D 3; D001667:Binding, Competitive; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004100:Dihydroxycholecalciferols / Q000097:blood*; D006801:Humans; D011485:Protein Binding
chemical_list: D004100:Dihydroxycholecalciferols; D015650:24,25-Dihydroxyvitamin D 3
vernacular_title: Dosaggio della 24,25-diidrossivitamina D per competizione di legame proteico.