1987 Fiscal Year Final Research Report Summary
A study of the effect of hormone and growth factor on liver regeneration
| Project/Area Number |
61570337
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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 |
Gastroenterology
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| Research Institution | Kyoto University |
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Principal Investigator |
FUKUDA Yoshihiro School of Medicine, Kyoto University, Assistant, 医学部, 助手 (50127130)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Liver regeneration / Protooncogene / C-fos / C-myc / C-Ha-ras / Estrogen receptor / Vitamin D receptor / myc遺伝子産物 |
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| Research Abstract |
In an attempt to elucidate the mechanisms of liver regeneration, the changes of protooncogene expression (c-myc, fos, Ha-ras, erbA), estrogen receptor (ER) and vitamin D receptor (VDR) were investigated in rat regenerating liver at different times after partial hepatectomy(PH).
Levels of c-fos mRNA elevated quickly to 2.5-fold within 45 min after PH and also decreased rapidly by 1h, c-myc mRNA reached maximal level of 3 fold at 3h and fell to basal level within 8h. Levels of c-Ha-ras elevated to 2-fold at 12h, but c-erbA mRNA did not demonstrate any significant increase during liver regeneration. Alternatively, c-myc mRNA were also demonstrated in hepatocyte cytoplasm by in situ hybridization method at 3h and myc protein product in hepatocyte nuclei at 6th immunohistochemically.
Recently, a close relationship between oncogene products and hormone receptor or growth factor or its receptor were indicated, therefore we investigated ER and VD-R which have some association with erbA and myc genes respectively. ER rapidly declined to 1/2-fold of basal level at 3h, despite no change in erbA. VD-R which was not detected in preoperative liver, became detectable and reached a peak at 6h after PH.
Hence, the parallelism in change of c-myc and VD-R expression suggested that there is a close relationship between c-myc and VD-R expression in hepatocyte. To investigate whether estrogens are able to promote liver regeneration, we treated rat with estradiol before PH. However, we were unable to obtain a result which indicated that estrogen raises significantly liver volume in 7 days, although ER stayed at a low level for long duration compared to non treated rats.
Unfortunately the evaluation of the effect of active vitamin D and growth factor, especially epidermal growth factor on liver regeneration remains to be done.
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