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

Purpose This study aims to investigate the effect of gonadotropin-releasing hormone agonist (GnRHa) on 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 the growth velocity in girls with central precocious puberty (CPP) during treatment. Methods Data was collected from 97 girls, aged below 9 years, diagnosed with precocious puberty and treated with GnRHa for at least 1 year in Kangdong Sacred Heart Hospital from 2014 to 2015. Their body height, weight, change in height standard deviation scores (∆SDSs), serum IGF-1, serum IGFBP-3, bone age (BA), and -202 A/C IGFBP-3 promoter polymorphism were measured before and after GnRHa treatment. Interrelationship between the variables was further calculated. Results During treatment, height SDS, IGF-1 SDS, IGFBP-3 SDS, and IGF-1/IGFBP-3 ratio significantly decreased. Significant correlations were observed between the ∆IGF-1 SDS and ∆height SDS (r = 0.405, p < 0.001). The presence of C allele was significantly correlated with IGF-1 SDS after the treatment (p = 0.049) and IGFBP-3 SDS before and after the treatment respectively, (p = 0.012 and p = 0.001) but not with ∆IGF-1 SDS, ∆IGFBP-3 SDS, ∆IGF-1/IGFBP-3 ratio, or ∆height SDS. Conclusion Growth velocity during GnRHa treatment is related to ∆IGF-1 SDS, concluding the apparent impact of GnRHa on the GH-IGF-1 axis. -202 A/C IGFBP-3 promoter polymorphism does not affect the growth velocity of GnRHa in CPP girls.