title: Increased bone formation by intermittent parathyroid hormone administration is due to the stimulation of proliferation and differentiation of osteoprogenitor cells in bone marrow.
abstract: In order to examine the mechanism of the anabolic effect of parathyroid hormone (PTH) on bone formation, human PTH(1-34) [hPTH(1-34)] (30 micrograms/kg) was injected subcutaneously to 9-week-old rats 5 times a week for 1 or 3 weeks. Trabecular bone volume (BV/TV) in the tibial metaphysis was not significantly different between the PTH- and vehicle-treated groups, but the parameters related to bone formation, including osteoid surface (OS/BS), mineralizing surface (MS/BS), mineral apposition rate (MAR), and bone formation rate (BFR/BS), were significantly increased as early as 1 week after PTH treatment. And the parameters related to bone resorption including eroded surface (ES/BS) and osteoclast number (N.Oc/BS) were also significantly increased as early as 1 week after PTH treatment. Treatment with PTH for 1 week induced no significant increase in bone mineral density at the femoral metaphysis, whereas the same treatment for 3 weeks induced a significant increase. When bone marrow cells isolated from femora and tibiae of either PTH- or vehicle-treated rats were cultured at a high density (2 x 10(7) cells/one well of 24-multiwell plate), cellular alkaline phosphatase (ALP) activity was significantly increased in the cells isolated from PTH-treated rats compared with vehicle-treated rats. When bone marrow cells were cultured at a low density (4 x 10(6) cells/a one well of 6-multiwell plate) to generate colonies (colony forming unit-fibroblastic, CFU-F), PTH induced apparent increases in both the total number of CFU-F and the number of ALP-positive CFU-F.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Orthopaedic Surgery, Niigata University School of Medicine, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nishida
authors.forename: A
authors.initials: A
authors.lastname: Yamaguchi
authors.forename: T
authors.initials: T
authors.lastname: Tanizawa
authors.forename: N
authors.initials: N
authors.lastname: Endo
authors.forename: T
authors.initials: T
authors.lastname: Mashiba
authors.forename: Y
authors.initials: Y
authors.lastname: Uchiyama
authors.forename: T
authors.initials: T
authors.lastname: Suda
authors.forename: S
authors.initials: S
authors.lastname: Yoshiki
authors.forename: H E
authors.initials: HE
authors.lastname: Takahashi
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000187:drug effects; D001846:Bone Development / Q000187:drug effects*; D001853:Bone Marrow / Q000187:drug effects; D001854:Bone Marrow Cells; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D005260:Female; D005269:Femur / Q000187:drug effects; D006801:Humans; D007279:Injections, Subcutaneous; D010010:Osteoclasts / Q000187:drug effects; D010281:Parathyroid Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects*; D019379:Teriparatide; D013977:Tibia / Q000187:drug effects
chemical_list: D010281:Parathyroid Hormone; D010446:Peptide Fragments; D019379:Teriparatide; D000469:Alkaline Phosphatase