TY - JOUR
T1 - Cortical bone growth and maturational changes in dwarf rats induced by recombinant human growth hormone
AU - Martinez, D. A.
AU - Orth, M. W.
AU - Caer, K. E.
AU - Vanderby, R.
AU - Vailas, A. C.
PY - 1996
Y1 - 1996
N2 - The growth hormone (GH)-deficient dwarf rat was used to investigate recombinant human (rh) GH-induced bone formation and to determine whether rhGH facilitates simultaneous increases in bone formation and bone maturation during rapid growth. Twenty dwarf rats, 37 days of age, were randomly assigned to dwarf plus rhGH (GH; n = 10) and dwarf plus vehicle (n = 10) groups. The GH group received 1.25 mg rhGH/kg body wt two times daily for 14 days. Biochemical, morphological, and X-ray diffraction measurements were performed on the femur middiaphysis. rhGH stimulated new bone growth in the GH group, as demonstrated by significant increases (P < 0.05) in longitudinal bone length (6%), middiaphyseal cross-sectional area (20%), and the amount of newly accreted bone collagen (28%) in the total pool of middiaphyseal bone collagen. Cortical bone density, mean hydroxyapatite crystal size, and the calcium and collagen contents (μg/mm3) were significantly smaller in the GH group (P < 0.05). Our findings suggest that the processes regulating new collagen accretion, bone collagen maturation, and mean hydroxyapatite crystal size may be independently regulated during rapid growth.
AB - The growth hormone (GH)-deficient dwarf rat was used to investigate recombinant human (rh) GH-induced bone formation and to determine whether rhGH facilitates simultaneous increases in bone formation and bone maturation during rapid growth. Twenty dwarf rats, 37 days of age, were randomly assigned to dwarf plus rhGH (GH; n = 10) and dwarf plus vehicle (n = 10) groups. The GH group received 1.25 mg rhGH/kg body wt two times daily for 14 days. Biochemical, morphological, and X-ray diffraction measurements were performed on the femur middiaphysis. rhGH stimulated new bone growth in the GH group, as demonstrated by significant increases (P < 0.05) in longitudinal bone length (6%), middiaphyseal cross-sectional area (20%), and the amount of newly accreted bone collagen (28%) in the total pool of middiaphyseal bone collagen. Cortical bone density, mean hydroxyapatite crystal size, and the calcium and collagen contents (μg/mm3) were significantly smaller in the GH group (P < 0.05). Our findings suggest that the processes regulating new collagen accretion, bone collagen maturation, and mean hydroxyapatite crystal size may be independently regulated during rapid growth.
KW - collagen accretion
KW - collagen cross-links
KW - density
KW - extracellular matrix
KW - hydroxyapatite
KW - porosity
UR - http://www.scopus.com/inward/record.url?scp=0030021319&partnerID=8YFLogxK
U2 - 10.1152/ajpendo.1996.270.1.e51
DO - 10.1152/ajpendo.1996.270.1.e51
M3 - Article
C2 - 8772473
AN - SCOPUS:0030021319
SN - 0193-1849
VL - 270
SP - E51-E59
JO - American Journal of Physiology - Endocrinology and Metabolism
JF - American Journal of Physiology - Endocrinology and Metabolism
IS - 1 33-1
ER -