A Gonadotropin-Releasing Hormone (GnRH) Stimulation Test Before and After GnRH Analogue Treatment for Central Precocious Puberty: Has the GnRH Test been Adequately Simplified?

Objective: To investigate and simplify the gonadotropin-releasing hormone (GnRH) stimulation test for assessing pubertal activation and suppression. Methods: The authors identified 72 girls diagnosed with central precocious puberty who were treated with a GnRH analogue (GnRHa). Patients who underwent an assessment regarding GnRHa-mediated puberty suppression had been diagnosed via the GnRH stimulation test prior to GnRHa treatment. The authors analyzed the diagnostic values of the during/before-treatment LH levels at different time points by a receiver-operating characteristic (ROC) curve. Results: Before GnRHa treatment, the mean luteinizing hormone (LH) level was higher at the 30-min test time point than at baseline or the 15, 60, 90, and 120-min points (P < 0.001). After GnRHa treatment, the LH levels were suppressed in 62 patients (86.1%) and inadequately suppressed in 10 (13.9%). The LH level was higher at the 30-min test time point than those at baseline or the 45 and 60-min level (P < 0.001). The area under the curve in a post-GnRHa treatment was greatest at 30 min. Conclusions: The simplified GnRH test is adequate for evaluating pubertal activation (30 and/or 45-min time points of the GnRH test) and suppression (the 30-min time point).