Efficacy of a Single Luteinizing Hormone Measurement after GnRH Agonist Administration for Therapeutic Monitoring of Girls with Central Precocious Puberty

Abstract

Purpose: The effectiveness of gonadotropin releasing hormone (GnRH) agonist therapy in central precocious puberty (CPP) depends on the suppression of luteinizing hormone (LH) secretion. The purpose of this study was to determine the utility of a single luteinizing hormone measurement after GnRH agonist injection for the therapeutic monitoring of CPP. Methods: The study included 148 females with CPP who had been treated with GnRH agonist. During the therapy, suppression of their pubertal development was assessed based on their height standard deviation score (SDS), bone age, and pubertal stage. Every six months, their serum LH and follicular stimulating hormone (FSH) levels were measured using immunoradiometric assays. Their estradiol levels were also assayed using radioimmunoassay two hours following GnRH agonist administration. Results: The means of the onset age, bone age, and chronological age were 7.2 ± 0.93, 10.1 ± 1.1, and 8.2 ± 0.94 years, respectively. Eight patients had pathologic intracranial lesions including harmatoma, hydrocephalus, meningitis, astrocytoma, and Rathke’s cleft cyst. The basal and peak LH levels were 1.56 ± 1.1 and 18.2 ± 12.1 IU/L, respectively. In 39 females with CPP, pubertal development was not sufficiently suppressed even after one year of therapy. The receiver operating characteristic (ROC) curve showed a cutoff value of LH for pubertal suppression of less than 2.5 IU/L. The area under the curve (AUC) was 0.674. Conclusion: The cutoff value of 2.5 IU/L for a LH measurement, taken two hours following subcutaneous GnRH agonist injection, is adequate for therapeutic monitoring of females with CPP. This method is both convenient and cost effective.