title: [Effect of sequential application of calcitonin and parathyroid hormone on bone remodeling process, an experimental research].
abstract: OBJECTIVE
  To investigate the effect of sequential application of calcitonin and parathyroid hormone (PTH) on bone remodeling process.
  
  
  METHODS
  Twelve female rats were divided equally into 2 groups: experimental group and control group. 1 U/100 g of calcitonin was injected intramuscularly to 6 rats for two days, and rrPTH in dosage of 30 micrograms was injected intramuscularly in the fourth and fifth days. At the sixth day their lumbar vertebral bodies were resected. Undecalcified and decalcified bone sections were made to be observed by optical microscopy and electronic microscopy. Bone histomorphological parameters were measured. Normal saline and solvent of the same volume were injected intramuscularly to the controls.
  
  
  RESULTS
  The OS/BS (%), O. Th (micron), N.Ob.S (cell/mm), and Vos/TV (%) were 19.9% +/- 6.2%, 3.4 microns +/- 0.4 micron, 37.6 cells/mm +/- 4.6 cells/mm, and 1.8% +/- 0.6% respectively in the experimental group, significantly higher than those in the control group (P < 0.05). After the PTH administration, more and plumper osteoblasts were observed. They were rich in rough endoplasmic reticulum, mitochondria, and Golgi apparatus.
  
  
  CONCLUSIONS
  Sequential application of calcitonin and parathyroid hormone obviously promotes the bone formation process. Both sites of bone remodeling formation and sites of bone modeling formation, especially the latter, increase.
authors.affiliation: Department of Orthopaedics, Third Hospital of Peking University, Beijing 100083, China.
authors.forename: F
authors.initials: F
authors.lastname: Zhang
authors.forename: G
authors.initials: G
authors.lastname: Dang
mesh_terms: D000818:Animals; D016723:Bone Remodeling / Q000187:drug effects*; D002116:Calcitonin / Q000008:administration & dosage / Q000494:pharmacology*; D004359:Drug Therapy, Combination; D066298:In Vitro Techniques; D008159:Lumbar Vertebrae / Q000187:drug effects / Q000648:ultrastructure; D008297:Male; D010024:Osteoporosis / Q000188:drug therapy; D010281:Parathyroid Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011917:Rats, Inbred Lew; D017208:Rats, Wistar
chemical_list: D010281:Parathyroid Hormone; D002116:Calcitonin