[The ultrastructure of the hepatocytes during the adaptation of rats to cold]

Albino rats were kept at about 0 degrees C during 42 days. Hepatocytes were found to have greater amount of mitochondria, lysosomes, peroxisomes. Considerable reserves of glycogen were also noted. It speaks of high energetic potential of hepatic cells which may be considered as the most important criterion of cold adaptation. On the other side, signs of decreased protein synthesis in hepatocytes (decreased relative volume of granular endoplasmic reticulum, less number density of ribosomes related to membranes) are thought to be an indication of inhibition of the specific secretory function of the organ which might be "the pay for adaptation" of organism to low temperatures.