消脂素的间接碘标记法与直接碘标记法的对比研究

Comparative study of indirect and direct iodination to leptin

间接碘标记法是先以氯胺T(ch-T)法标记对羟基苯丙酸琥珀酰亚胺脂(Bolton-hunter试剂,BH试剂),制备125I-BH,然后于冰浴中与LEP联结,得到125I-LEP;直接碘标记法是以ch-T法按常规对LEP直接进行标记。结果显示,间接碘标记法标记的125I-LEP放射性比活度为1.43MBq/μg,125I的总标记率为37.8%,所建立的RIA的灵敏度为0.25μg/L,在45天内标准曲线(0.5～30μg/L)稳定,B:B0位于92.7%～17.5%到94.6%～22.8%之间。直接法制备的125I-LEP,放射性比活度为1.79MBq/μg,125I的总标记率为41.4%,方法灵敏度为0.37μg/L。在44天内标准曲线(0.5～30μg/L)亦较稳定,B:B0位于87.7%～23.7%到91.4%～35.2%之间。表明两方法的标准曲线稳定性在45天内差异不大,均能满足临床工作的需求。

125I-LEP was prepareded by 125I with indirect iodination and direct iodination respectively to develop RIA for method comparison. For the indirect iodination, BH agent was iodinated by ch-T, then conjugated to leptin in ice bath. For the direct iodination, LEP was iodinated by ch-T with direct method. The specific radioactivity of 125I-LEP with indirect iodination was 1.43 MBq/μg, the total labeling rate of 125I was 37.8%, the sensitivity was 0.25 μg/L. The standard curve （0.5-30 lag/L） was stability with the B：Bo from 92.7%-17.5% to 94.6%-22.8% in 45 days. For the direct iodination, the specific radioactivity of 125I-LEP was 1.79 MBq/lag, the total labelling rate of 1251 was 41.4%, the sensitivity was 0.37 lag/L. The standard curve （0.5-30 μg/L） was stability with the B/Bofrom 87.7%-23.7% to 91.4%-35.2% in 44 days. The standard curve stability of the 125I-LEP prepared by the indirect iodination was not much better than that by the direct iodination in 45 days. They can satisfy the needs in clinic use. Which were worth of additional exploration to enhance the quality in RIA of LEP.