| Objective To investigate consecutive patterns of urinary gonadotropin (UGn) duringgonadotropin-releasing hormone analogue (GnRHa) stimulation testing in girls withcentral precocious puberty (CPP) as a basic research data for diagnosing the function ofhypothalamic-pituitary-gonadal axis (HPGA) in children.Methods Forty-four GnRHa stimulation tests (during the diagnostic evaluation in allof24girls with CPP, as well as3months after the beginning of GnRHa therapy in20/24girls), and consecutive patterns of UGn were observed during the tests (decapeptyl,0.1mg,08:30a.m., s.c.).Timed12h diurnal and nocturnal urine were collected for detecting diurnaland nocturnal UGn before the tests, respectively. The first12h urine, the second12h urine,the third12h urine, the second overnight urine, the third overnight urine and the fourthovernight urine after decapeptyl injection were collected in44,44,10/44,44,31/44and25/44tests, respectively. In addition, one normal early pubertal girl, one normal latepubertal girl and one adult female were recruited for GnRHa stimulation tests, respectively.Consecutive timed3h urine samples for each one from those three normal females wererespectively collected within24h before decapeptyl injecting, and within48h during thetests. The luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were assayedby immunochemiluminometric assays (ICMA), and UGn concentrations were corrected forcreatinine (Cr).Results (1) Serum peak gonadotropin (Gn) levels: Twenty-four girls were inaccordance with the standard for diagnosing CPP, and before GnRHa therapy their serumpeak LH (PLH) and peak FSH (PFSH) were respectively (25.25±17.56) IU·L-1and(17.00±7.58) IU·L-1, respectively.Nineteen in20cases had good clinical efficacy, and PLHand PFSH were respectively (0.97±0.38) IU·L-1and (1.67±0.96) IU·L-1after GnRHatherapy. And the other1in20cases had poor clinical efficacy, whose PLH and PFSH were2.52IU·L-1and3.60IU·L-1, respectively.(2)The profiles and levels of UGn:1)Before GnRHa therapy: The levels of UGn/Cr displayed significantly elevated within24h (Thelevels of UGn/Cr in the first12h urine were higher than ones in diurnal spontaneous urine,and the second12h urine were higher than ones in nocturnal spontaneous urine, P=0.000)in response to GnRHa stimulation testing. The median for urinary LH (ULH)/Cr in the first12h was24.7times diurnal spontaneous urine and for the second12h was16.8timesnocturnal spontaneous urine. The median for urinary FSH (UFSH)/Cr in the first12h was8.0times diurnal spontaneous urine and for the second12h was7.7times nocturnalspontaneous urine. UGn/Cr began to drop to spontaneous levels in the second overnighturine. The patterns of UGn/Cr in girls with CPP were similar to the profiles of normal girlsin puberty and adult female. The levels of UGn/Cr in the third overnight urine, the fourthovernight urine were lower than ones in nocturnal spontaneous urine.2) After GnRHatherapy: There was no difference in cases with good efficacy between the first12h urineduring the tests and diurnal spontaneous urine in ULH/Cr, as well as between the second12h urine during the tests and nocturnal spontaneous urine.(3)The correlationcoefficients between serum peak Gn and UGn: The correlation coefficients betweenserum PLH and spontaneous ULH/Cr were respectively0.345(diurnal urine),0.641(nocturnal urine). The correlation between serum PFSH and spontaneous UFSH/Cr were0.677(diurnal urine),0.723(nocturnal urine), respectively. The correlation between serumPLH and stimulated ULH/Cr were0.849(the first12h urine),0.835(the second12h urine),0.818(the third12h urine) and0.790(the second overnight urine), respectively. For serumPFSH and stimulated UFSH/Cr, the correlation were0.897(the first12h urine),0.863(thesecond12h urine),0.915(the third12h urine) and0.772(the second overnight urine),respectively. There was no difference in correlation between the former (correlationbetween stimulated UFSH/Cr in the second overnight urine and serum PFSH) and the latter(correlation between UFSH/Cr in nocturnal spontaneous urine and serum PFSH), exceptthat the correlation between stimulated UGn/Cr in the first12h urine and serum peak Gn,and the correlation between stimulated UGn/Cr in the third12h urine and serum peak Gnwere higher than the correlation between UGn/Cr in diurnal spontaneous urine and serumpeak Gn. The correlation between stimulated UGn/Cr in the second12h urine and serumpeak Gn, and the correlation between stimulated UGn/Cr in the second overnight urine andserum peak Gn were higher than the correlation between UGn/Cr in nocturnal spontaneousurine and serum peak Gn (△Z>1.96).(4)The detection of UGn: All UFSH concentrations were detectable for girls with CPP before and after GnRHa therapy. Before GnRHa therapy,there were66.7%,91.7%,100%,100%and87.5%of ULH concentrations were detectablefor nocturnal spontaneous urine, the first12h urine, the second12h urine, the third12hurine and the second overnight urine, respectively.Conclusions The valuable duration of noninvasive UGn determinations by ICMAduring GnRHa stimulation testing for clinical research is within48h during the tests, andthe best time window may be within24h during the tests. There were high correlationcoefficients between stimulated UGn by ICMA and serum peak Gn in girls with CPP.Stimulated UGn can reflect serum Gn levels and may be better than spontaneous urine. Theconsecutive patterns of stimulated UGn/Cr in girls with CPP are similar to the ones of twonormal girls in puberty and an adult female. |
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