title: [Assay of serum 24,25-dihydroxycholecalciferol by a competitive protein binding method].
abstract: 24-25(OH)2 D3 is a vitamin D metabolite due to renal 24-hydroxylation of 25OHD3. The metabolite has some important biological functions on the bone and intestine. Its affinity to the D serum binding protein allows a competitive binding protein assay to be carried out as for 25OHD3, following a chromatographic purification step on Sephadex LH 20. Serum levels of the metabolite in 18 control subjects were found to be 2,69 +/- 1,34 ng/ml while 25OHD3 was 17,41 +/- 7,39 ng/ml and the ratio 24-25(OH)2D3 /25OHD3 in the serum was 0,15. The assay of 24-25(OH)2D3 is useful for physiological studies and for identification of vitamin D depletion states.
mesh_terms: D015650:24,25-Dihydroxyvitamin D 3; D001667:Binding, Competitive; D002112:Calcifediol; D002352:Carrier Proteins / Q000378:metabolism; D004100:Dihydroxycholecalciferols / Q000097:blood*; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood*; D008722:Methods; D014809:Vitamin D-Binding Protein
chemical_list: D002352:Carrier Proteins; D004100:Dihydroxycholecalciferols; D006887:Hydroxycholecalciferols; D014809:Vitamin D-Binding Protein; D015650:24,25-Dihydroxyvitamin D 3; D002112:Calcifediol
vernacular_title: Dosaggio del 24-25diidrossicolecalciferolo sierico con metodo di legame proteico competitivo.