Cortical bone growth and maturational changes in dwarf rats induced by recombinant human growth hormone

D. A. Martinez, M. W. Orth, K. E. Caer, R. Vanderby, A. C. Vailas

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

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.

Original languageEnglish
Pages (from-to)E51-E59
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume270
Issue number1 33-1
DOIs
StatePublished - 1996

Keywords

  • collagen accretion
  • collagen cross-links
  • density
  • extracellular matrix
  • hydroxyapatite
  • porosity

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