title: Effects of intermittent administration of low dose human PTH(1-34) on cancellous and cortical bone of lumbar vertebral bodies in adult beagles.
abstract: This study assessed the effect of low dose human parathyroid hormone [hPTH(1-34)] administration on cancellous and cortical bone of lumbar vertebrae in intact male beagles. 16 19-20-month-old beagle dogs were randomized into four groups: in group 1, the vehicle control group, saline was injected daily; in group 2, the sequential group, 0.375 microg/kg of PTH was injected daily for 4 weeks, then off 8 weeks, and this sequence was once repeated for another 4 and 8 weeks; in group 3, the same dose of PTH was injected once per week for 24 weeks; and, in group 4, PTH was injected three times per week for 24 weeks. Histomorphometric assessment on cancelllous and cortical bone (both ventral and dorsal shell) and two-dimensional node-strut analysis were done on the fifth lumbar vertebral bodies after calcein double bone labeling. In intact adult beagles, on the group treated with 0.375 microg/kg per day three times per week (group 4): (1) had a higher mean value in cancellous bone formation parameters [osteoid surface (+74%), osteoid volume (twofold), mineral apposition rate (+21%), and bone formation rate (twofold)]; (2) exhibited no effect on cortical thickness and porosity in both the ventral and dorsal shell; and (3) showed a lower mean value of node to termini (0.11 +/- 0.02 vs. 0.22 +/- 0.09) and a higher mean value of cortex to node (0.18 +/- 0.06 vs. 0.08 +/- 0.02), but not in trabeculae to trabeculae node, than age-related controls. In conclusion, we found that a low dose of PTH administration: (1) stimulated cancellous bone formation; (2) improved connectivity of trabeculae joined to the cortex; (3) did not decrease cortical thickness; and (4) did not increase cortical porosity in both ventral and dorsal cortexal shell of the lumbar vertebrae during this dosage and period in intact male beagles.
authors.affiliation: Department of Orthopaedic Surgery, Niigata University School of Medicine, Niigata City, Japan.
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.forename: H E
authors.initials: HE
authors.lastname: Takahashi
authors.forename: J
authors.initials: J
authors.lastname: Inoue
authors.forename: T
authors.initials: T
authors.lastname: Tanizawa
authors.forename: N
authors.initials: N
authors.lastname: Endo
authors.forename: N
authors.initials: N
authors.lastname: Yamamoto
authors.forename: M
authors.initials: M
authors.lastname: Hori
mesh_terms: D000818:Animals; D001798:Blood Proteins / Q000187:drug effects / Q000378:metabolism; D001835:Body Weight; D015519:Bone Density / Q000187:drug effects; D001842:Bone and Bones / Q000033:anatomy & histology / Q000187:drug effects*; D002118:Calcium / Q000097:blood; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008159:Lumbar Vertebrae / Q000033:anatomy & histology / Q000187:drug effects*; D008297:Male; D010012:Osteogenesis / Q000187:drug effects; D010281:Parathyroid Hormone / Q000008:administration & dosage*; D010446:Peptide Fragments / Q000008:administration & dosage*; D010758:Phosphorus / Q000097:blood; D016062:Porosity / Q000187:drug effects; D019379:Teriparatide / Q000008:administration & dosage*
chemical_list: D001798:Blood Proteins; D010281:Parathyroid Hormone; D010446:Peptide Fragments; D019379:Teriparatide; D010758:Phosphorus; D002118:Calcium