Effect of long-term administration of a high protein or low protein diet on rat liver. Morphological and biochemical findings.

An increase in relative liver weight, the total liver DNA content, hepatocyte volume and the total surface area of the membranes of mitochondria and the granular and smooth endoplasmic reticulum of hepatocytes, but a decrease in the size of the nuclei, were found in adult male rats fed three weeks on a high protein diet compared with animals given a standard laboratory diet. Serum transaminase (ALT, AST) and alkaline phosphatase activity was practically the same as the control values. Rats fed three weeks on a low protein diet showed a decrease in relative liver weight, in the total liver DNA content, in hepatocyte and nuclear volume and in ploidy, and also in the surface area of the membranes of the mitochondria and the smooth and granular endoplasmic reticulum; conversely, the number of binucleate hepatocytes rose. Serum ALT, AST and alkaline phosphatase activity was mildly, but statistically significantly elevated.