Assessment of Estradiol Response after Depot Triptorelin Administration in Girls with Central Precocious Puberty

Background: Estradiol at baseline or after a classical gonadotropin-releasing hormone test did not reflect ovarian steroidogenesis in central precocious puberty (CPP) girls. Aims: To evaluate estradiol response to depot triptorelin, both at start and during therapy to determine how active ovarian steroidogenesis is at pubertal stage and under therapy. Methods: A prospective study was performed in 43 CPP girls. Serum luteinizing hormone and follicle-stimulating hormone at 3 h (LH-3h, FSH-3h) and estradiol at 24 h (E₂-24h) after injection of depot triptorelin 3.75 mg were measured, at first dose and at 3, 6, 12, 18 and 24 months of treatment. Results: E₂-24h after depot triptorelin was >100 pg/ml after the first dose. Estradiol response (E₂-24h) fell to levels <14 pg/ml in 78 out of 82 follow-up visits along 2 years of therapy. Concomitantly, LH-3h and FSH-3h were <4.0 and <6.3 IU/l, respectively. In 4 patients with inadequate treatment, E₂-24h, LH-3h and FSH-3h rose to pubertal values similar to those observed at first dose. Conclusion: Estradiol (<14 pg/ml) assessment 24 h after depot triptorelin administration is a reliable and simple manner to confirm ovarian suppression in CPP girls during treatment.