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Streaming liver. VII: DNA turnover in acinus zone-3
1H.H Humphrey Center for Experimental Medicine and Cancer Research, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Liver
|June 1, 1990
Summary
Hepatocyte nuclear size and DNA content decrease in liver zone 3, suggesting DNA leaves cells physiologically. This "deamplification" reverses gene amplification observed in other liver zones.
Area of Science:
- Hepatocyte biology
- Cellular physiology
- Molecular genetics
Background:
- Hepatocyte nucleus enlargement and polyploidy occur in liver zones 1 and 2.
- The behavior of hepatocytes in zone 3 regarding nuclear changes is less understood.
Purpose of the Study:
- To investigate nuclear area and DNA content changes in rat hepatocytes within zone 3.
- To determine if DNA accumulation or loss occurs in zone 3 hepatocytes.
Main Methods:
- Feulgen staining and image cytometry were used on rat liver sections.
- Hepatocyte nuclear area and DNA absorbance were measured at varying distances from terminal hepatic veins.
- Measurements were taken up to 220 microns, covering liver zones 2 and 3.
Main Results:
- Hepatocyte nuclear area and DNA absorbance significantly declined in zone 3.
- Zone 3 hepatocytes lose approximately 0.24 DNA absorbance units daily.
- This contrasts with DNA accumulation observed in zones 1 and 2.
Conclusions:
- A physiological process of DNA exit from intact cells is proposed for zone 3 hepatocytes.
- DNA loss in zone 3 may represent a reversal of gene amplification, or "deamplification".
- These findings offer new insights into hepatocyte nuclear dynamics and DNA regulation.