Post natal changes in the water and electrolyte content of rat liver.

Abstract

The water, sodium, potassium, chloride and fat content has been measured in livers of albino rats whose ages varied between a few minutes and 115 days and the findings expressed in terms of the fat‐free dry weight of the tissue. The size of the extracellular compartment of the tissue water has been deduced from the chloride content of the tissue, an allowance being made for intracellular chloride. During the first day after birth there was a rapid increase in the water and potassium content of the liver which was entirely accounted for by an increase in the size of the intracellular compartment of the tissue water. During the following 2 days the liver water and potassium content and the size of the intracellular water compartment decreased again. It is suggested that these changes may be related to alterations in the concentration of anions in the liver cells. Between the ages of 3 and 32 days there was a decrease in the water, sodium and chloride content of the whole tissue which could be accounted for by a decrease in the size of the extracellular compartment of the tissue water. The size of the intracellular water compartment remained constant during this time, nevertheless there was a decrease in the tissue potassium content. After the age of 32 days there was little change in the gross composition of the liver but there was a reduction in the quantity of tissue water which was free of chloride. Diurnal effects and those of fasting and of weaning on the liver composition are also described.