EFFECTS OF GROWTH-HORMONE THERAPY ON THE DEVELOPMENTAL-CHANGES OF FOLLICLE-STIMULATING-HORMONE AND INSULIN-LIKE GROWTH FACTOR-I SERUM CONCENTRATIONS IN TURNERS-SYNDROME

OBJECTIVE The aim was to investigate whether, in the absence of gonads, GH could bring forward the age of neuroendocrine activation resulting in onset of puberty. DESIGN In girls with Turner's syndrome, we evaluated the effects of GH therapy on developmental changes in FSH serum concentrations used as an indicator of neuroendocrine maturation in the absence of gonads. PATIENTS Thirty-nine girls with Turner's syndrome aged 4.0-17.1 years were treated using GH (25 IU/m2 week) for 1 year. MEASUREMENTS Serum levels of FSH and IGF-I were measured before initiation of GH therapy and 12 months later, after interruption of GH treatment for 2 days. RESULTS Pretreatment FSH levels were low between 6 and 10 years and increased markedly at 10-11 years of age. This pattern was unchanged after 1 year of GH therapy. Pretreatment IGF-I levels were positively correlated with age and they were uniformly increased after 1 year of GH therapy. CONCLUSIONS Our data suggest that GH and its effector, IGF-I, do not influence the timing of the onset of puberty through an effect on its neuroendocrine control.