1995 Fiscal Year Final Research Report Summary
Mechanism of action of androgen in human hair follicles
| Project/Area Number |
06670872
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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 |
Dermatology
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| Research Institution | Osaka University (1995)
大分医科大学 (1994) |
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Principal Investigator |
ITAMI Satoshi Osaka University, Department of Dermatology, Associate professor, 医学部, 助教授 (30136791)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAYASU Susumu Oita Medical University, Department of Dermatology, Professor and Chairman, 医学部, 教授 (20028468)
SONODA Tadashige Oita Medical University, Department of Dermatology, Instructor (80244169)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Hair / Dermal papilla cells / Androgen / 5alpha-reductase / Androgen receptor / IGF-I |
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| Research Abstract |
In order to study the mechanism of action of androgen in human hair follicles, we examined the expressions of androgen receptor, type I and type II 5alpha-reductase in cultured human hair follicle cells. Beard dermal papilla cells possess a higher 5alpha-reductase activity and a larger amount of androgen receptors than reticular dermal fibroblasts or dermal papilla cells from the occipital scalp. Besides, the enzyme found in beard dermal papilla cell appears to be type 2 5alpha-reductase. In contrast, outer root sheathe cells do not have characteristics of the target cells. Androgen significantly stimulates the proliferation of outer root sheath cells that are cocultured with beard dermal papilla cells without cell contact. The expression of insulin-like growth factorI (IGF-I) mRNA in beard dermal papilla cells was stimulated by androgen and antagonized by cyproterone acetate. Outer root sheath cells did not express mRNA for IGF-I either in the presence or absence of androgen. Both of these two types of cells expressed mRNA for IGF-I receptor and the expression was not affected by androgen. Neutralizing antibody against IGF-I antagonized the stimulatory effect of androgen on the growth of outer root sheath cell cocultured with beard dermal papilla cells. These findings suggest that IGF-I is a candidate for androgen induced hair growth factors.
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