Carlström K
Department of Obstetrics and Gynecology, Karolinska Institutet, Huddinge University Hospital, Sweden.
Acta Obstet Gynecol Scand Suppl. 1996;163:11-5.
Measurement of low peripheral concentrations of estradiol-17 beta with radioimmunoassay techniques has frequently produced extremely variable results, due to methodological problems. One such problem is variable non-specifically bound radioactivity (NSB) in methods using precipitation for separation of free and bound radioactivity. This problem can be overcome either by substituting the precipitation technique with dextran coated charcoal separation which drastically reduces NSB or by correcting for individual NSB values in samples and calibrators. These simple modifications of an existing commercial kit make convenient determination of estradiol-17 beta at low concentrations in postmenopausal women possible. Estrone sulfate is the quantitatively most important circulating estrogen in non-pregnant individuals. Studies of the metabolism of tritiated estrone sulfate in vitro evidently show that estrone sulfate is converted into estradiol-17 beta in several estrogen target tissues, including the vaginal mucosa. This conversion is probably important for the estradiol-17 beta supply to target organs in individuals with low circulating levels of estradiol-17 beta such as postmenopausal women.
由于方法学问题，采用放射免疫分析技术测量外周血中低浓度的雌二醇-17β常常会产生极不稳定的结果。其中一个问题是，在使用沉淀法分离游离和结合放射性的方法中，非特异性结合放射性（NSB）存在变化。这个问题可以通过用葡聚糖包被活性炭分离法替代沉淀技术来解决，该方法可大幅降低NSB，或者通过校正样品和校准品中的个体NSB值来解决。对现有商用试剂盒进行这些简单修改后，就可以方便地测定绝经后女性低浓度的雌二醇-17β。硫酸雌酮是未孕个体中循环雌激素的最重要定量成分。体外对氚标记硫酸雌酮代谢的研究明显表明，硫酸雌酮在包括阴道黏膜在内的多个雌激素靶组织中转化为雌二醇-17β。这种转化对于雌二醇-17β循环水平较低的个体（如绝经后女性）向靶器官供应雌二醇-17β可能很重要。
