| Project/Area Number |
15500437
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Sports science
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| Research Institution | Kanazawa University |
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Principal Investigator |
KITAURA Takashi Kanazawa University, Health Service Center, Associate Professor, 保健管理センター, 助教授 (00143868)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2004: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2003: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | clenbuterol / osteoclast / COX--2 / bone resorptive cytokine / turobuterol / isoproterenol / UCP3 / MyoD / 筋肥大 / 速筋化 / 乳酸トランスポーター / RT-PCR法 / クロストーク / 破骨細胞誘導因子 |
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| Research Abstract |
In this study, we tried to examine the longitudinal inhibitory growth effects on bone of clenbuterol (beta-2 adrenergic receptor agonist) using reverse-transcription polymerase chain reaction (RT-PCR) analysis of the cultured osteoclast cells derived from mouse bone marrow cells with calcitriol (10 nM)and dexamethasone (10 nM). During the differentiation process from preosteoclasts into the matured osteoclasts, the clenbuterol were administered into the culture system. Clenbuterol increased the number of osteoclasts. The both of tulobuterol and isoproterenol also increased the osteoclasts. But the selective beta-2 antagonist (butoxamine) and H89 (protein kinase A inhibitor) inhibited the increased osteoclasts. It suggested the increased osteoclasts might be induced by the increased cAMP.
It is well known that the PGE2 accelerate the forming of osteoclasts. The mRNA expression of COX-2 which is PGE2 synthetase also increased with the treatments of clenbuterol, turobuterol, and isoproterenol. Furthermore, the mRNA expression of bone resorptive cytokines, IL-1β and IL-6 were increased by clenbuterol, which also accelerated the bone forming by the osteoblasts activation... These results suggested that this clenbuterol affected more strongly on osteoclast forming system but a little on osteoblast. It means that these drugs have the activating action on various cells but the whole effects are complicated. Therefore, the using of these drugs should be careful.
We confirmed that clenbuterol increased the expression of mRNAs of UCP3 which increases lipolysis and MyoD which is nuclear regulatory factor. They suggested that clenbuterol increased the MyoD as the myogenic master regulator and might induce the muscle hypertrophy and the transformation from slow-to fast-twitch muscle.
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