The effect of growth hormone on insulin-like growth factor I and bone metabolism in distraction osteogenesis.
Limb lengthening in the left tibia of 30 mature female Yucatan micropigs was performed using distraction osteogenesis. A treatment group of 15 animals received recombinant porcine growth hormone (r-pGH) (100 microg/kg/day) while the others served as controls. Serial serum measurements of total insulin-like growth factor I (IGF-I), free IGF-I, IGF binding proteins -1, -2, -3 and -4 (IGFBP-1 to -4) were performed. Bone-specific alkaline phosphatase (bone-ALP) and the serum carboxyl-terminal telopeptide of type I collagen (ICTP) were measured as bone turnover markers. The GH-treated animals showed a significant increase in total IGF-I, free IGF-I and IGFBP-3 after surgery (P<0.001). Similarly, the treated animals showed a significantly higher level of bone-ALP (P<0.001) throughout the experiment compared to the controls. There was a significant correlation between bone-ALP and total IGF-I (r=0.76) in the GH-treated group and an even higher correlation for free IGF-I (r=0.90). There was no difference in the ICTP serum levels between the two groups. These data indicate that the application of species-specific growth hormone results in a stimulation of bone formation in distraction osteogenesis which may be mediated by IGF-I. The stronger correlation between free IGF-I and bone-ALP indicates that the anabolic effect of IGF-I may be regulated through the IGFBPs by binding and inactivating IGF-I.
Bail
H J
HJ
Trauma and Reconstructive Surgery, Humboldt University of Berlin, Germany. hermann.bail@charite.de
Kolbeck
S
S
Lindner
T
T
Dahne
M
M
Weiler
A
A
Windhagen
H J
HJ
Raun
K
K
Skjaerbaek
C
C
Flyvbjerg
A
A
Ørskov
H
H
Haas
N P
NP
Raschke
M J
MJ
D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D001842:Bone and Bones / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D013006:Growth Hormone / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D010012:Osteogenesis / Q000187:drug effects* / Q000502:physiology; D011994:Recombinant Proteins / Q000494:pharmacology; D013552:Swine; D013556:Swine, Miniature
D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D000469:Alkaline Phosphatase