1993 Fiscal Year Final Research Report Summary
Study of TGF-beta on developing of Nifedipine-induced gingival overgrowth
| Project/Area Number |
03670895
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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 |
Conservative dentistry
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| Research Institution | The University of Tokushima, University of Dental Hospital |
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Principal Investigator |
SHINOHARA Hiroyuki The University of Tokushima, School of Dentistry, Research associate, 歯学部, 助手 (60175388)
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| Project Period (FY) |
1991 – 1993
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| Keywords | nifedipine / gingival overgrowth / rat / adverse effect / calcium antagonist |
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| Research Abstract |
Nifedipine, calcium antagonist, is known to induce gingival overgrowth as an adverse effect, but the pathogenesis has not been elucidated yet. Using an experimental model which we established in rats, this study was aimed to clarify whether serum levels of nifedipine, duration of the drug administration, aging, or differences of sex affect the nifedipine-induced gingival overgrowth. Gingival overgrowth was not appreciable till the serum level reached to the maximum level, about 800 ng/ml, however, once the concentration is increased to the level, a marked gingival overgrowth occurred. Time course experiments revealed that a duration of 30 day's oral administration of the drug was enough to induce the overgrowth, but longer periods of the administration did not result in any further increase of the overgrowth. Withdrawal of nifedipine resulted in spontaneous recession of the induced-gingival overgrowth to normal gingival in a time-dependent manner. When the administration was started at different ages, 20, 50 and 90 day-old, respectively, for 55 days, gingival overgrowth was induced only in youngest rats, but not in others. The plasma levels in female rats showed significantly high of the maximum levels in male rats at the same concentrations of nifedipine in diet, but essetially no differences in the magnitude between male and female rats were found. These result suggest that there exists a threshold plasma concentration, preference for younger ages, no preference for either sex on the nifedipin-induced gingival overgroeth in rats.
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