The morphogenesis of the vacuolation of liver cells.

The morphogenesis of the vacuolation of liver cells caused by congestion was studied in the rat. Congestion of the liver was produced by constriction of the inferior vena cava just below the diaphragm. Vacuoles appeared within 5 min after the constriction (inferior vena cava pressure: 50 mm H2O or more). Vacuolation began as a small and saccular invagination of the sinusoidal surface of the liver cell membrane, and at the initial stage the vacuolar lumen connected with the space of Disse through a narrow slit. The small vacuoles increased in size and became larger by fusing with each other. The limiting membrane of vacuoles showed identical enzymological activities to those in the liver cell membrane. Vacuoles contained some components of blood and horseradish peroxidase injected into the femoral vein. These findings suggest that vacuolation of liver cells is formed by invaginations of liver cell membrane.