Abstract
Low levels of LH and FSH in serum cannot be reliably assayed by RIA. We report the development of two ultrasensitive time-resolved immunofluorometric assays (IFMA) for these gonadotropins. Two monoclonal antibodies are used in each assay. One antibody is immobilized onto the wall of plastic microtiter strips wells and the other one is labeled with a europium chelate. The immobilized antibody is specific for the β subunit of either LH or FSH and the labeled antibody for the α subunit of both gonadotropins. Twenty-five μl of sample is diluted with 200 μl assay buffer and incubated overnight in the wells. The assay sensitivity for LH was 0.019 IU/l and for FSH 0.014 IU/l. A linear measuring range was obtained up to 200 IU/l for both assays. In girls aged 7-9 years the mean LH level was 0.05 IU/l and the FSH level 0.8 IU/l. Until 10 yrs of age a rapid increase of LH to 0.6 IU/l was observed and a further slower increase to 5.1 IU/l in adults. The FSH pattern was similar to that of LH but the increase was more shallow and the mean level in adults was 4.7 IU/l. The increase in LH level was 100-fold, whereas that of FSH was only 7-fold. The increase in serum estradiol levels followed the same pattern as LH, but the mean increase in estradiol was only about 10-fold.
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Alfthan, H., Apter, D. & Stenman, UH. MEASUREMENT OF LH AND FSH BY ULTRASENSITIVE TIME-RESOLVED IMMUNOFLUOROMETRIC ASSAYS PREDICT THE ONSET OF PUBERTY. Pediatr Res 23, 128 (1988). https://doi.org/10.1203/00006450-198801000-00164
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DOI: https://doi.org/10.1203/00006450-198801000-00164
