Correlation between plasma membrane surface area and transferrin secretion rate in isolated hepatocytes

Area of Science:

• Cell biology
• Hepatocyte function
• Exocytosis

Background:

• Exocytosis typically involves vesicle fusion with the plasma membrane without cell size increase.
• Factors regulating this process and its impact on secretory activity are not well understood.

Purpose of the Study:

• To investigate the relationship between plasma membrane surface area and secretory activity in rat hepatocytes.
• To determine if hepatocyte size influences transferrin secretion.

Main Methods:

• Isolated rat hepatocytes were prepared using liver collagenase perfusion.
• Transferrin secretion was measured at the single-cell level using the reverse hemolytic plaque assay.
• Hepatocyte and hemolytic plaque surface areas were calculated and analyzed.

Main Results:

• A significant correlation was found between hepatocyte surface area and hemolytic plaque surface area.
• The ratio of transferrin secreted to hepatocyte surface area remained constant regardless of hepatocyte size.
• This finding was confirmed using automatic image analysis.

Conclusions:

• Hepatocyte plasma membrane surface area may be a limiting factor in transferrin secretion.
• The regulation of exocytosis and its impact on cell size warrants further investigation.