1992 Fiscal Year Final Research Report Summary
Biochemical Studies on Liver Functions in Primary Cultured Hepatocytes of Old Rats
| Project/Area Number |
02670305
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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 | Tottori University |
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Principal Investigator |
MURA Tetsuo Division of Chemistry, Steroid Research, Tottori University School of Medicine, Lecture, 医学部, 講師 (80093631)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Primary cultured of old rat hepatocytes / Low cell density culture / Fatty acid synthesis by glucagon / Bile acid conjugation / Peroxisome and bile acid synthesis / Desmosterol conversion / Hydroxylation of bile acid by dexamethasone / EGF receptor assay |
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| Research Abstract |
Many metabolic functions besides proliferation are regulated by cell density and that there is a reciprocal relation between cell growth and expression of hepatocyte-specific functions. On the other hand, old rat hepatocytes in primary culture are well known not to respond normally to EGF. Therefore, we examined whether any reciprocal related between cell growth and expression of hepatocyte-specific functions could be demonstrated in old rat hepatocytes by change in cell density or addition of plasma membranes protein from adult and old rat liver.
The following results were obtained : (1)The effect of glucagon on fatty acid synthesis at old rat hepatocytes was lower than that of adult rats. (2)Norepinephrine stimulation of DNA synthesis was lower at the presence of insulin and EGF (3)When the old rat hepatocytes were cultured at low cell density, the dexamethasone increased taurin conjugation of the dihydroxylated bile acids, and reversibly the hydroxylation of deoxycholate in the 6 beta and 7alpha position was decreased.
These results are interesting to speculate on how old hepatocytes lose the ability to respond to the cell-surface mulator during aging. Cell-cell contact could be considered as being analogues to the interaction of hormones with surface receptors.
The interaction between cells could produce an intracellular signal that is responsible for suppression of cell growth and expression of tissue-specific functions.
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