title: [Radioimmunologic assay of steroids. Comparison of 3H- and 125I-ligands].
abstract: Characteristic properties of radioimmunoassay (RIA) of steroids with 3H- and 124I-ligands as a label were studied using two anabolic steroids methandrostenolone and 19-nortestosterone. Antisera towards 124I-steroids were used at higher dilutions as their specific activity was distinctly more than in the antisera to 3H-substances. However, 125I-steroid must be in a stereochemical correspondence with the antiserum otherwise antibodies do not bind the label. The antisera towards 3H-steroids were obtained after coupling of a carrier at any position of the steroid molecule. Standard curves for 3H-steroids were very steep; this pattern of the curves enabled to increase the accuracy of calculations. Sensitivity of RIA with 3H-label was also higher as compared with 125I-steroids in the experiments where unlabelled steroids inhibited the label binding with antibodies by 50%. Distinct differences were not observed in RIA specificity for methandrostenolone and 19-nortestosterone.
mesh_terms: D045930:Anabolic Agents / Q000032:analysis*; D055598:Chemical Phenomena; D002621:Chemistry; D007457:Iodine Radioisotopes; D011863:Radioimmunoassay; D012015:Reference Standards; D014316:Tritium
chemical_list: D045930:Anabolic Agents; D007457:Iodine Radioisotopes; D014316:Tritium
vernacular_title: Radioimmunnoe opredelenie steroidov. Sravnenie 3H- i 125I-ligandov.