SERUM INSULIN-LIKE GROWTH-FACTOR-I (IGF-I) AND IGF BINDING PROTEIN-3 LEVELS IN CHILDREN WITH PRECOCIOUS PUBERTY TREATED WITH GONADOTROPIN-RELEASING-HORMONE ANALOG WITHOUT OR IN COMBINATION WITH CYPROTERONE-ACETATE

In artier to assess the behavior of growth hormone, insulin-like growt h factor-I (IGF-I) and ICF binding protein-3 (IGFBF-3) in girls with c entral precocious puberty treated with gonadotropin-releasing hormone (GnRH) analog therapy, we studied 14 girls with this condition; the pa tients were subdivided into two groups, according to the therapy follo wed. Group A (n = 7; age 4.2-7.1 years) received GnRH analog in combin ation with cyproterone acetate, and Group B (n = 7; age 4.4-6.9 years) received long-acting analog alone. Before treatment, IGF-I levels wer e significantly increased compared to healthy age-matched children in the two groups (447 +/- 33 mu g/l for Group A and 435 +/- 38 mu g/l fo r Group B vs. control 175 +/- 78 mu g/l; p < 0.01). Moreover, serum IG FBP-3 levels were significantly higher than the age-related reference range far IGFBP-3 (4478.2 +/- 178 mu g/l for Group A and 4532.3 +/- 16 7 mu g/l for Group B vs. control 2905 +/- 641 mu g/l; p < 0.01). Durin g the two years of gonadal suppression, Group A patients showed a sign ificant decrease in IGF-I and IGFBP-3 levels, while in Group B there w as no significant change in IGF-I; moreover, in Group B, IGFBP-3 level increased significantly compared to baseline values during the first year of treatment (4532.3 +/- 167 mu g/l vs. 5410.3 +/- 169 mu g/l; p < 0.05) and decreased significantly at the end of the second year of t reatment (3816.1 +/- 189 mu g/l vs. 5410.3 +/- 169 mu g/l; p < 0.01). Our study skews that the two different treatments of precocious pubert y (with and without cyproterone acetate) have different effects on ICF -I and IGFBP-3, and suggests that there growth factors are under diffe rent metabolic regulation.