Voprosy meditsinskoi khimii (ISSN 0042-8809)

Radioimmunologic assay of steroids. Comparison of 3H- and 125I-ligands

Morozov V.I., Chaĭkovskiĭ V.S.
PubMed Id: 4049783
Year: 1985 vol: 31  issue:4  pages: 131-135
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.
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Reference: Morozov V.I., Chaĭkovskiĭ V.S., Radioimmunologic assay of steroids. Comparison of 3H- and 125I-ligands, Voprosy meditsinskoi khimii, 1985, vol: 31(4), 131-135.