Background: The degree of suppression of the pituitary-ovarian axis in girls with central precocious puberty (CPP) under GnRH analogue (GnRHa) treatment is usually assessed at pituitary levels. However, the extent of ovarian function suppression under GnRHa treatment has not been evaluated.
Objective: To evaluate ovarian activity in CPP girls before and during treatment with GnRHa.
Patients and methods: In this prospective study, 11 CPP girls naïve of treatment were included. Serum LH, FSH, estradiol (E2, ECLIA) and inhibin B (INH-B, ELISA) were measured at baseline, 3 and 24 h after depot Triptorelin acetate 3.75 mg IM administration at the first and after 4th, 7th and 13th doses. Samples were obtained at 3 and 24 h at the time of maximal gonadotrophin and ovarian responses respectively.
Results: 3 h after the first GnRHa dose LH and FSH (mean±SEM) increased significantly over baseline (1.9±0.79 to 22.2±3.9 IU/l and 4.6±0.46 IU/l to 19.9±1.9 IU/l, P<0.001 respectively); 24 h after, E2 and INH-B increased ten and five times over baseline (24±8250±42 pg/ml and 53±5263±30 pg/ml respectively, P<0.001). A positive correlation between E2 and INH-B was observed (r=0.84, P<0.001). Throughout subsequent GnRHa doses, 3 h gonadotrophin responses were suppressed (LH<4 IU/l), and 24 h after GnRHa, E2 and INH-B levels fell below normal prepubertal levels and remained within the detection limit of the assays. Nevertheless, three patients with poor adherence to treatment protocol showed gonadotrophin, E2 and INH-B responses to GnRHa at pubertal levels.
Conclusion: After 24 h of the first dose of GnRHa, increased E2 and INH-B serum levels confirm pubertal activation of ovarian function. Under sustained GnRHa treatment, when gondotrophin suppression is reached, ovarian endocrine function is almost negligible.
01 - 03 Oct 2015
European Society for Paediatric Endocrinology