Study on the Changes in Bone Metabolism with Growth Hormone Treatment in Children with Growth Hormone Deficiency: Changes in the Serum Levels of Bone Markers

Kim, Eun Young; Yang, Sei Won

Abstract

PURPOSE: Growth hormone(GH) plays a major role in postnatal longitudinal bone growth. Exogenous growth hormone leads to stimulation of bone resorption as well as formation. The aim of this study is to observe the changes in the indices of bone metabolism and the correlation between growth velocity and changes in the levels of bone markers with GH treatment in children with GH deficiency(GHD).
METHODS
Blood samples were collected from 12 patients before and 6 and 12 months after GH therapy. We measured bone-specific alkaline phosphatase(B-ALP), osteocalcin, and carboxy- terminal propeptide of type I collagen(PICP) as markers for bone formation, and cross-linked C-telopeptide of type I collagen(ICTP) as a marker for bone resorption.
RESULTS
All patients showed significant increases in both height velocity(P<0.001), and height SD score(P<0.001) with GH therapy. The concentration of B-ALP increased after 12 mos of GH therapy(P<0.05). The maximal osteocalcin levels reached at 6 months of therapy(P<0.05), and decreased to near baseline level afterward. The concentration of PICP and ICTP significantly increased after 12 months of GH therapy(P<0.05). The percent of increase in serum B-ALP level during the first 6 months of GH treatment significantly correlated with increase in height SD score during the first year of GH therapy(P<0.005).
CONCLUSION
GH treatment in children with GHD leads to activation of osteoclasts and osteoblasts as evidenced by increased biochemical markers of bone resorption and formation. The changes in the serum level of B-ALP during the first 6 months of therapy appears to be a useful marker for predicting growth responses during the first year of GH therapy.