Estradiol levels in prepubertal boys and girls - analytical challenges

Increasing evidence points at an important function of low concentrations of estradiol (E-2) in prepubertal boys and girls. E-2 serum levels in prepubertal children are, however, often immeasurable in conventional E-2 assays. This strongly hampers further investigation of the physiological relevance of E-2 in children. In addition, there is an increasing concern of the potential effect of exposure to endocrine disrupters with estrogenic or antiandrogenic activity on pubertal development. A requirement of assessing the instance for this concern, adds further to the demands for applicable methodologies for the evaluation of the sensitivity of the organism to low E-2 concentrations. Traditionally, E-2 is measured by use of the radioimmunoassay (RIA). As an ultrasensitive alternative to the RIA, a recombinant cell bioassay has been developed. In this review, methodological aspects for these methods of analysis are examined and their applicability for evaluation of low E-2 serum concentrations in children is estimated. Furthermore, available data on E-2 levels in prepubertal boys and girls are evaluated and discussed, taking into consideration the limitations of the methods of analysis. In conclusion, there is a pronounced demand for new and improved methods of analysis for accurate and sensitive evaluation of low concentrations of E-2.