A morphometric study of the effects of short-term starvation on rat hepatocytes.

Short-term (24 h) starvation induced a significant decrease in the liver weight and in the average volume of hepatocytes, together with a notable decrease in the hepatic concentration of proteins, glycogen, cholesterol and triglycerides. Hepatocyte atrophy was due for about 95% to the decrease in the membrane space, in which glycogen and endoplasmic reticulum membranes are contained, and for about 5% to the depletion of lipid droplets, in which cholesterol and triglycerides are stored. Nuclei, mitochondria and rough endoplasmic reticulum did not display appreciable modifications. The smooth endoplasmic reticulum underwent a net decrease, comparable with the decrease in the liver protein content, and the volume of dense-body compartment was increased, mainly through the rise in the number of microautophagic vacuoles and secondary lysosomes. These last findings were interpreted as the morphological counterpart of the fasting-induced enhancement of protein degradation in rat liver.