| Objective To investigate kinetics of gonadotropin in urine by immunochemiluminometric assays (ICMA) during gonadotropin-releasing hormone analog (GnRHa) stimulation testing as a pilot study for diagnosing the pubertal hypothalamic- pituitary-gonadal axis (HPGA) in children.Methods Twenty three GnRHa stimulation testing in children who suffered from disorders of growth or pubertal development were performed in hospital. Nocturnal spontaneous urine before injecting triptorelin, and 9 consecutive timed urine samples (the first was timed 1.5-hour urine, and the others were respectively timed 1-hour) were collected respectively after injecting triptorelin in 23 tests, and 3 consecutive overnight urine were collected respectively in 15/23 tests. The luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were assayed by ICMA, and urinary gonadotropin (UGn) concentrations were corrected by creatinine(Cr).Results (1)The secretion for the peak urinary luteinizing hormone (ULH) among 9 consecutive timed urine sampels: The upper 95% confidence limit of time (median) for the first peak ULH and the highest peak ULH(the quantities of ULH and ratio of ULH concentrations/Cr) were respectively 4h~6.2h and 7.2h~9.5h, and the number(median) of peaks and the upper 95% confidence limit were 3 peaks and 4 to 4.75 peaks respectively.(2)The peak UGn among the consecutive timed urine samples: The correlation coefficient between serum peak luteinizing hormone (PLH) and the first peak quantities of ULH was 0.934, and between serum PLH and the the highest peak quantities of ULH 0.855, and between serum PLH and the first peak ratio of ULH concentrations/Cr 0.851, and between serum PLH and for the highest peak ratio of ULH concentrations/Cr 0.841; the areas under the receiver operating characteristic (ROC)curves of above-mentioned four indexes for the diagnoses of onset of HPGA were 1.000,0.917,0.939 and 0.886, respectively. The correlation coefficient between serum PLH/peak stimulated FSH (PFSH) and (the first peak quantities of ULH)/(quantities of UFSHs) was 0.836(UFSHs was the quantities of urinary FSH in the same first peak ULH sample), and between serum PLH/PFSH and (the highest peak quantities of ULH)/(quantities of UFSHs) 0.856, and between serum PLH/PFSH and (the first peak ratio of ULH concentrations/Cr)/(the ratio of UFSHs concentrations/Cr) 0.875, and between serum PLH/PFSH and for (the highest peak ratio of ULH concentrations/Cr)/(the ratio of UFSHs concentrations/Cr) 0.832;the areas under the ROC curves of above-mentioned four urinary indexes for the diagnoses of onset of HPGA were 0.955, 0.902, 0.932 and 0.894, respectively.(3)UGn in timed 1.5-hour to timed 9.5-hour urine (for example, timed 3.5-hour urine was the mixture of the first timed 1.5-hour and the second timed 1 hour and the third timed 1 hour):The correlation coefficient between serum PLH and the quantities of ULH from the timed 2.5-hour to the timed 9.5-hour urine were 0.932, 0.955, 0.977, 0.977, 0.932, 0.947, 0.955, 0.962 and 0.962 respectively; for serum PLH and the ULH concentrations/Cr 0.881, 0.931, 0.924, 0.931, 0.901, 0.904,0.904, 0.897 and 0.887 respectively; for serum PLH/PFSH and ULH/UFSH 0.711, 0.752, 0.833, 0.862, 0.857, 0.836, 0.828, 0.821 and 0.819 respectively; the areas under the ROC curves of the quantities of ULH(in timed 1.5-hour to timed 9.5-hour urine)for the diagnoses of onset of HPGA were 0.932, 0.955, 0.977, 0.977, 0.932, 0.947, 0.955, 0.962 and 0.962 respectively; for the ULH concentrations/Cr 0.939, 0.955, 0.962, 0.977, 0.924, 0.924, 0.924, 0.924 and 0.924 respectively; for the ULH/UFSH 0.856, 0.909, 0.962, 0.947, 0.924, 0.932, 0.924, 0.924 and 0.932 respectively.(4)Kinetics of UGn in overnight urine:The correlation coefficient between serum PLH and nocturnal spontaneous ratio of ULH concentrations/Cr in 15/23 tests was 0.489, for serum PLH and the first overnight ratio of ULH concentrations/Cr after injecting triptorelin 0.818, for serum PLH and the second overnight ratio of ULH concentrations/Cr 0.357, for serum PLH and the third overnight ratio of ULH concentrations/Cr 0.393, the areas under the ROC curves of above-mentioned four urinary index for the diagnoses of onset of HPGA were respectively 0.893, 1.000, 0.875 and 0.821, the medians for the overnight ratio of ULH concentrations/ Cr after injecting triptorelin were higher than that in nocturnal spontaneous ULH concentrations/Cr,but ULH concentrations/Cr in the second overnight urine decreased to the level of the nocturnal spontaneous ULH concentrations/Cr. (P>0.05).(5)Nocturnal spontaneous urinary gonadotropin(Gn)and serum spontaneous Gn: The correlation coefficient between serum PLH and the nocturnal spontaneous quantities of ULH was 0.760 in 23 tests, for serum PLH and nocturnal spontaneous ratio of ULH concentrations/ Cr 0.750,for serum PLH and the serum spontaneous LH(SLH) 0.699. The correlation coefficient between serum PLH/PFSH and ULH/UFSH was 0.540, for serum PLH/PFSH and the SLH/spontaneous FSH(SFSH) 0.586; the areas under the ROC curves of above-mentioned five urinary indexes for the diagnoses of onset of HPGA were 0.955, 0.939,0.939, 0.955 and 0.598 respectively.Conclusions Our data suggest that there was good correlation between consecutive timed UGn and serum peak Gn determined by ICMA during GnRHa stimulation testing in children. The values of consecutive timed UGn during GnRHa stimulation testing were better than nocturnal spontaneous UGn or serum spontaneous Gn for the diagnosis of onset of HPGA. The effectiveness of triptorelin on pituitary happened mainly in the first 24h after its injection in children.
|
PDF Full Text Request