The alteration of IGF-1 levels and relationship between IGF-1 levels and growth velocity during GnRH analogue therapy

Abstract

Background: Some studies have examined the effect of gonadal suppression on insulin-like growth factor-1 (IGF-1) levels and the growth velocity (GV) with conflicting results.Methods: Forty-four girls treated with gonadotropin-releasing hormone analogue (GnRHa) for central precocious puberty (CPP) were included in the study. IGF-1 levels were examined at the beginning and after 12 months of treatment.Results: IGF-1 and IGF-1 standard deviation score (SUS) according to chronological age (CA-IGF-1 SUS) at diagnosis were positively correlated with chronological age (CA), anthropometric measurements, stage of puberty, bone age (BA), BA-CA, follicle-stimulating hormone (FSH), luteinising hormone (LH), oestradiol, uterus length, endometrium thickness and ovarian volume (OV) at diagnosis (p <0.05). There was no significant difference in IGF-1 levels after treatment. However, there was a negative correlation between Delta IGF-1 SDS and IGF-1 level, CA-IGF-1 SDS and BA-IGF-1 SDS at diagnosis (p <0.05). There was no correlation between GV and IGF-1, Delta IGF-1. GV was negatively correlated with basal LH level at diagnosis (p = 0.008, r=-0.397). Peak LH levels of the patients who had GV-SDS <0 were more suppressive than those of the patients who had GV-SDS> 0 after 12 months of treatment. Conclusions: It was determined that the IGF-1 level and CA-IGF-1 SDS at baseline were correlated with more advanced pubertal stage prior to treatment. Initiation of treatment with a relatively high level of IGF-1 increased the risk of a decrease in the IGF-1 level. Likewise, the initiation of treatment with a relatively high LH level may increase the risk of low GV, but low GV was not related to the IGF-1 level. Increased sex steroid suppression may increase the risk of low GV.