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Regulation of cell membrane function and secretion by extracellular fluid viscosity
1Department of Biochemistry, Hebrew University, Hadassah Medical School, Jerusalem, Israel.
Biorheology
|January 1, 1990
Summary
Elevated extracellular fluid viscosity (EFV) inhibits cellular functions, including lipoprotein secretion and enzyme activity. This suggests EFV plays a key regulatory role in biological processes.
Area of Science:
- Biochemistry
- Cell Biology
- Physiology
Background:
- Plasma viscosity increases in pathological conditions due to elevated protein and macromolecule levels.
- The impact of extracellular fluid viscosity (EFV) on cellular and biochemical functions requires investigation.
Purpose of the Study:
- To examine how elevated EFV affects cultured liver cells and red blood cells.
- To investigate the underlying mechanisms, focusing on cell membrane components like Gangliosides (GMs) and phospholipase A2 (PLA2).
Main Methods:
- Modified EFV using various macromolecules in cell cultures.
- Measured lipoprotein and lysosomal enzyme secretion from liver cells.
- Assessed effects of EFV on GMs degradation and cell membrane PLA2 activity.
- Examined PLA2-induced erythrocyte hemolysis at varying EFV.
Main Results:
- Increased EFV inhibited lipoprotein and lysosomal enzyme secretion by liver cells.
- Elevated plasma viscosity in hyperlipidemic rats decreased lipoprotein levels.
- EFV elevation decreased GMs degradation rate and inhibited cell membrane PLA2 activity.
- Increased EFV inhibited erythrocyte hemolysis induced by snake venom PLA2.
Conclusions:
- Extracellular fluid viscosity significantly impacts cellular functions, including secretion and membrane enzyme activity.
- PLA2 inhibition by EFV is a key mechanism underlying observed cellular effects.
- EFV may be a crucial regulator of general cellular and biochemical processes.