ESPE Abstracts

Objectives: We explored the alternative of using overnight fold change in gonadotropin levels by comparing the last-night-voided and first-morning-voided urine concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) as a conceptual analogy to the invasive gonadotropin-releasing hormone (GnRH) stimulation test setting.

Methods: We investigated the nocturnal changes in the immunoreactivity levels of urinary gonadotropins between early and late prepubertal stages as well as between early and late pubertal stages in FMV and LNV urine samples from 30 girls, of whom the prepubertal ones were further investigated through follow-up visits within the one-year-period from the start of the study.

Results: ROC analysis revealed that the FMV total U-LH and FMV U-FSH concentrations at or above 0.3 IU/L and 2.5 IU/L, respectively were excellent predictors of a forthcoming onset of puberty within one year (100% sensitivity, 100% specificity, AUC: 1.00 and n=10, for both). FMV total U-LH concentration at or above 0.8 IU/L represented the cut-off for clinical signs of puberty. An overnight increase (FMV/LNV ratio) in total U-LH concentrations and in the U-LH/U-FSH ratio at or below 1.2-fold in pubertal girls was associated with the postmenarchal pubertal stage.

Conclusion: FMV total U-LH and U-FSH above 0.3 IU/L and 2.5 IU/L, respectively can be used as cut-off values to predict the manifestation of the clinical signs of puberty within one year. FMV total U-LH concentrations 0.3-0.8 IU/L and 0.6 IU/L may represent the range and the threshold, respectively, that reflect the loosening of the central brake on the GnRH pulse generator.