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Cortical bone growth and maturational changes in dwarf rats induced by recombinant human growth hormoneThe 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 (microgram/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.
Document ID
Document Type
Reprint (Version printed in journal)
Martinez, D. A.
(University of Wisconsin-Madison 53706 United States)
Orth, M. W.
Carr, K. E.
Vanderby, R. Jr
Vailas, A. C.
Date Acquired
August 22, 2013
Publication Date
January 1, 1996
Publication Information
Publication: The American journal of physiology
Volume: 270
Issue: 1 Pt 1
ISSN: 0002-9513
Subject Category
Aerospace Medicine
Distribution Limits
NASA Discipline Musculoskeletal
Non-NASA Center
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