2001 Fiscal Year Final Research Report Summary
Development of drugs targeting neurosteroid-metabolizing enzymes
| Project/Area Number |
11557195
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
医薬分子機能学
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| Research Institution | Gifu Pharmaceutical University |
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Principal Investigator |
HARA Akira Gifu Pharmaceutical University, Pharmaceutical Science, Professor, 薬学部, 教授 (00094334)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIKURA Syuhei Gifu Pharmaceutical University, Pharmaceutical Science, Assistant, 薬学部, 助手
USAMI Noriyuki Gifu Pharmaceutical University, Pharmaceutical Science, Assistant, 薬学部, 助手 (60257483)
DEYASHIKI Yoshihiro Gifu Pharmaceutical University, Pharmaceutical Science, Lecture, 薬学部, 講師 (00202193)
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| Project Period (FY) |
1999 – 2001
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| Keywords | hydroxysteroid dehydrogenase / neurosteroids / genetic polymorphism / structure-function relationship / inhibitor / activator / gene-expression regulation / gene transfection |
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| Research Abstract |
3α-Hydroxysteroid dehydrogenase (HSD) and 20α-HSD in animal brains have been shown to be involved in the synthesis and metabolism of neuroactive steroids. In humans, one 20α-HSD and three 3α-HSDs (type 1 - 3) are present, and the roles of the enzymes in the neurosteroid metabolism are unknown, but clinical investigations provide evidence for an involvement of the neuroactive steroids in conditions such as premenstrual syndrome, catamenial epilepsy and depressive disorders. This study focused the following six points on the two human enzymes as targets for developing new drugs for management of such disorders.
1. Roles of the human enzymes in the neurosteroid metabolism. Tissue distribution and substrate specificity for neurosteroids of the enzymes suggest that in the brain 20α-HSD inactivates the neuroactive steroids and their precursor, progesterone, and that 3α-HSD type 3 is involved in the synthesis of the neuroactive steroids.
2. Search of activators and inhibitors. Only 3α-HSD type
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1 was activated by several therapeutic drugs and thyroxine. Of several inhibitors for the enzymes, benzbromarone and its derivatives specifically and strongly inhibited 20α-HSD, which suggests that they are lead compounds to develop the drugs.
3. Structure-function relationship of the enzymes. The site-directed mutagenesis study of 20α-HSD and 3α-HSD type 1 identified or suggested several amino acids in their active centers and binding sites for the activators and inhibitors. The crystallographic study of 20α-HSD is now in progress.
4. Regulation of gene expression. Ethacrynic acid enhanced the expression of the enzymes, except 3α-HSD type 1 in several cultured human cells. The investigation of expression of liver-specific 3α-HSD type 1 indicated that three hepatocyte nuclear factors regulate the transcription of the enzyme gene.
5. Genetic polymorphism. Analyses of expressed mRNA and gene for 3α-HSD type 1 in specimens identified a variant gene which encodes a enzyme with low catalytic activity.
6. Establishment of evaluation system for drugs using cells and animals transfected with the enzymes or their genes The system using the cells was established, but that using the animal models could not be achieved, because the expression of the enzyme was too little to affect the brain function. The establishment of the latter system will be continued. Less
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Research Products
(14 results)
