Relationship between growth velocity and change of levels of insulin-like growth factor-1, insulin-like growth factor binding protein-3 and, IGFBP-3 promoter polymorphism during GnRH agonist treatment

PURPOSE: This study aims to investigate the effect of gonadotropin-releasing hormone agonist (GnRHa) on the growth hormone (GH)-insulin-like growth factor-1 (IGF-1) axis and to evaluate whether -202 A/C IGF binding protein-3 (IGFBP-3) promoter polymorphism affects growth velocity in females with central precocious puberty (CPP) during treatment. METHODS: Data was collected from 97 females younger than 9 years, diagnosed with precocious puberty and treated with GnRHa for at least 1 year at Kangdong Sacred Heart Hospital from 2014 to 2015. Their body height, weight, change in height standard deviation score (∆SDS), serum IGF-1, serum IGFBP-3, bone age, and -202 A/C IGFBP-3 promoter polymorphism were measured before and after GnRHa treatment. The interrelationships between the variables were calculated. RESULTS: During treatment, height SDS, IGF-1 SDS, IGFBP-3 SDS, and IGF-1/IGFBP-3 ratio significantly decreased. A significant correlation was observed between ∆IGF-1 SDS and ∆height SDS (r=0.405, P<0.001). The presence of the C allele was significantly correlated with IGF-1 SDS after treatment (P=0.049) and with IGFBP-3 SDS before and after treatment (P=0.012 and P=0.001), but not with ∆IGF-1 SDS, ∆IGFBP-3 SDS, ∆IGF-1/IGFBP-3 ratio, or ∆height SDS. CONCLUSIONS: Growth velocity during GnRHa treatment is related to ∆IGF-1 SDS, indicating the apparent impact of GnRHa on the GH-IGF-1 axis. The -202 A/C IGFBP-3 promoter polymorphism does not affect the growth velocity of GnRHa in CPP girls.