title: The influence of combined parathyroid hormone and growth hormone treatment on cortical bone in aged ovariectomized rats.
abstract: The influence of combined parathyroid hormone (PTH) and growth hormone (GH) treatment on bone formation and mechanical strength was investigated in femoral middiaphysial cortical bone from 20-month-old ovariectomized (OVX) rats. The animals were OVX at 10 months of age, and at 18 months they were treated daily for 56 days with PTH(1-34) alone (60 microg/kg), recombinant human GH (rhGH) alone (2.7 mg/kg), or a combination of PTH(1-34) plus rhGH. Vehicle was given to OVX control rats. All animals were labeled at day 28 (calcein) and at day 49 (tetracycline) of the treatment period. PTH(1-34) alone gave rise to formation of a new zone of bone at the endocortical surface. rhGH alone caused substantial bone deposition at the periosteal surface without influencing the endocortical surface. Combined PTH(1-34) plus rhGH administration enhanced bone deposition at the periosteal surface to the same extent as that of rhGH alone. However, the combined treatment resulted in a more pronounced formation of new bone at the endocortical surface than was induced by PTH(1-34) alone. Both PTH(1-34) alone and rhGH alone increased the mechanical strength of the femoral diaphysis, and further increase in mechanical strength resulted from combined PTH(1-34) plus rhGH treatment. OVX by itself induced the characteristic increase in medullary cavity cross-sectional area and a minor decrease in the mechanical quality of the osseous tissue.
authors.affiliation: Department of Connective Tissue Biology, Institute of Anatomy, University of Aarhus, Denmark.
authors.forename: T T
authors.initials: TT
authors.lastname: Andreassen
authors.forename: H
authors.initials: H
authors.lastname: Oxlund
mesh_terms: D000367:Age Factors; D000818:Animals; D015519:Bone Density; D001846:Bone Development / Q000187:drug effects; D001842:Bone and Bones / Q000187:drug effects*; D018483:Diaphyses / Q000187:drug effects; D005260:Female; D005269:Femur / Q000187:drug effects / Q000254:growth & development; D019382:Human Growth Hormone / Q000494:pharmacology*; D008903:Minerals / Q000378:metabolism; D010052:Ovariectomy; D010281:Parathyroid Hormone / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000494:pharmacology; D013314:Stress, Mechanical
chemical_list: D008903:Minerals; D010281:Parathyroid Hormone; D011994:Recombinant Proteins; D019382:Human Growth Hormone