Assessment of Gonadotropin Concentrations Stimulated by Gonadotropin-Releasing Hormone Analog by Electrochemiluminescence in Girls with Precocious Puberty and Premature Thelarche.

OBJECTIVE: The aim of this study is to determine the cutoff values of gonadotropin response to gonadotropin-releasing hormone analogs (GnRHas) corresponding to the activation of the hypothalamic-pituitary-gonadal axis that could differentiate central precocious puberty (CPP) from premature thelarche (PT) and using the electrochemiluminescence assay method. METHODS: A total of 49 girls underwent the stimulation test with an intramuscular injection of 3.75 mg leuprolide acetate. Based on the clinical and laboratory characteristics, they were divided into two groups: CPP (n = 22) and PT (n = 27). Baseline estradiol, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were collected before GnRHa administration and LH and FSH at 60 and 120 min, respectively, after GnRHa administration. RESULTS: The girls with CPP presented an increased height Z-score, advanced bone age, and higher baseline LH, FSH, estradiol, and LH/FSH ratio in relation to PT (p < 0.001). Stimulated LH differed significantly between the two groups, and the LH cutoff values were ≥4.29 IU/L (p < 0.001) and ≥3.95 IU/L at 60 and 120 min, respectively (p < 0.001). The LH peak was found at 60 min after stimulation. CONCLUSIONS: The GnRHa test is effective in distinguishing CPP from PT, and a single sampling, at 60 min, with LH concentrations above 4.29 may be the parameter of choice with the advantage of greater convenience and practicality.

Clinical and Laboratory Parameters of Gonadotropin-Releasing Hormone Analog Treatment Effectiveness in Children with Precocious Puberty.

OBJECTIVE: There are no doubts about the clinical benefits of treatment with GnRH analogs for patients diagnosed with central precocious puberty (CPP). However, laboratory monitoring of CPP is still a matter of considerable controversy in the literature. Therefore, the main objective of this study was to evaluate the cut-off values of stimulated LH that determine gonadotrophic suppression. METHODS: Twenty-four girls, on treatment with leuprorelin acetate (LA) at 3.75 mg IM every 28 days, were studied. The clinical parameters used to indicate clinical effectiveness were regression or maintenance of sexual characteristics according to the Tanner stage, growth velocity reduction, reduction or maintenance of the difference between bone age and chronological age and maintenance or improvement of the final height prediction. For the laboratory effectiveness test, basal estradiol, LH, and FSH levels were collected before and 1 and 2 h after the administration of 3.75 mg LA. RESULTS: Eleven girls showed improvement in all clinical parameters, and their effectiveness tests were compared to those of the other patients to calculate the cut-off values, which were ≤3.64 IU/L (p=0.004*) for LH after 1 h and ≤6.10 IU/L (p<0.001*) for LH after 2 h. CONCLUSION: The LH response after the LA stimulation test, associated with clinical data and within a context of CPP, constitutes a reliable and feasible resource and can assist in monitoring the effectiveness of treatment.

Clinical and laboratory parameters of gonadotropin-releasing hormone analog treatment effectiveness in children with precocious puberty

OBJECTIVE: There are no doubts about the clinical benefits of treatment with GnRH analogs for patients diagnosed with central precocious puberty (CPP). However, laboratory monitoring of CPP is still a matter of considerable controversy in the literature. Therefore, the main objective of this study was to evaluate the cut-off values of stimulated LH that determine gonadotrophic suppression. METHODS: Twenty-four girls, on treatment with leuprorelin acetate (LA) at 3.75 mg IM every 28 days, were studied. The clinical parameters used to indicate clinical effectiveness were regression or maintenance of sexual characteristics according to the Tanner stage, growth velocity reduction, reduction or maintenance of the difference between bone age and chronological age and maintenance or improvement of the final height prediction. For the laboratory effectiveness test, basal estradiol, LH, and FSH levels were collected before and 1 and 2 h after the administration of 3.75 mg LA. RESULTS: Eleven girls showed improvement in all clinical parameters, and their effectiveness tests were compared to those of the other patients to calculate the cut-off values, which were ≤3.64 IU/L (p=0.004*) for LH after 1 h and ≤6.10 IU/L (p<0.001*) for LH after 2 h. CONCLUSION: The LH response after the LA stimulation test, associated with clinical data and within a context of CPP, constitutes a reliable and feasible resource and can assist in monitoring the effectiveness of treatment.