Influence of malnutrition on regeneration and composition of the liver in rats.

Using a new experimental model of protein-calorie starvation, the impact of malnutrition on liver regeneration, and the changes in liver composition during malnutrition and regeneration, were studied. Forty-one rats were allocated to one of 3 groups: group I (n = 13) were normally nourished rats which underwent partial hepatectomy, group II (n = 16) were semistarved rats which underwent partial hepatectomy, and group III (n = 12) were normally nourished rats which underwent sham operations. Liver biopsy specimens were taken at the time of partial hepatectomy and when the rats were killed after 48 hours of regeneration. The samples were used for determination of water, fat, glycogen, protein, DNA, and RNA content. The replication rate of liver cells was measured by autoradiography after continuous incorporation of tritium labelled thymidine. Malnutrition was associated with a higher postoperative mortality and a reduced rate of regeneration. The livers changed during malnutrition with a reduction in both size and glycogen concentration. After 48 hours of regeneration there was a marked change in liver composition with severe fatty degeneration, a fall in glycogen and a rise in water content. RNA concentration was stimulated during regeneration, but during malnutrition the protein content decreased. The results emphasise the importance of an adequate nutritional state for liver regeneration.