title: Estimation of the specific activity of radioiodinated gonadotrophins: comparison of three methods.
abstract: We compared 3 methods for estimating the specific activity of radioiodinated gonadotrophins. Two of the methods (column recovery and isotopic dilution) gave similar results, while the third (autodisplacement) gave significantly higher estimations. In the autodisplacement method, B/T ratios, obtained when either labelled hormone alone, or labelled and unlabelled hormone, are added to the antibody, were compared as estimates of the mass of hormone iodinated. It is likely that immunologically unreactive impurities present in the labelled hormone solution invalidate such comparison.
mesh_terms: D006063:Chorionic Gonadotropin / Q000032:analysis; D002852:Chromatography, Ion Exchange; D006062:Gonadotropins / Q000032:analysis*; D006801:Humans; D007457:Iodine Radioisotopes / Q000378:metabolism; D011863:Radioimmunoassay / Q000379:methods; D013972:Thyrotropin / Q000032:analysis
chemical_list: D006063:Chorionic Gonadotropin; D006062:Gonadotropins; D007457:Iodine Radioisotopes; D013972:Thyrotropin