1992 Fiscal Year Final Research Report Summary
Local Factors in Bone Metabolism of Experimental Osteoporosis
| Project/Area Number |
02670654
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Orthopaedic surgery
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| Research Institution | Ehime University |
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Principal Investigator |
OKUMURA Hideo Ehime University School of Medicine Associate Professor, 医学部, 助教授 (60115813)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Osteoporosis / Rat / Northern blot analysis / m-RNA / Local factor / Osteocalcin |
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| Research Abstract |
Human osteoporosis is induced by aging, menopause and immobilization. Various hormones which regulate calcium metabolism in the whole body and various local factors which regulate bone metabolism in local bony tissue affect on the pathophysiology of osteoporosis. The expression of mRNA of local factors in the bone cells of osteoporotic tissue induced by immobilization combined with ovariectomy was studied. The mRNA was analyzed by Northern blot method using cDNA probes. The osteocalcin mRNA level in the osteoporotic tibiae significantly increased. The TGF-beta mRNA level increased in bone marrow cells and slightly increased in bone cells in the osteoporotic tibiae. The experiment of administration of dexamethasone was also done. The osteocalcin mRNA level in the tibiae of the rats treated with dexamethasone significantly decreased. Suppressive effect of dexamethasone on osteocalcin expression was persistent for seven days at higher dose. Northern blot analysis showed that both 1,25(OH)_2D_3 and 2beta-(3-hydroxypropoxy)-1,25(OH)_2D_3 caused an increase in osteocalcin mRNA levels in bone. And they increased osteocalcin mRNA levels in osteoblast-like cells ( ROS17/2.8 ) in vitro. In conclusion, general factors ( estrogen, 1,25(OH)_2D_3 ) have an effect on the trascriptional regulation of local factors ( osteocalcin, TGF- beta ) in bone.
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