PROTEIN-SYNTHESIS IN REGENERATING RAT-LIVER DURING MALNUTRITION

To examine the effect of malnutrition on liver protein metabolism and synthesis during liver regeneration, 104 rats were allocated to semi-s tarvation or ordinary food intake for 1 week. Half of each group was s ham operated and the other half was partially hepatectomized. Specimen s were taken from the liver at the time of liver resection and from an imals killed 24, 48 and 72 h after the primary operation. Liver sample s were analysed for DNA and protein, and in the 48-h groups RNA and pr otein synthesis were also analysed. Protein synthesis was measured by the flooding method using L[4-H-3] phenylalanine. The liver weight dur ing regeneration increased very rapidly in the well-nourished animals, but when expressed as percent of body weight or as proportional incre ases, the difference between well-nourished and malnourished animals d isappeared. The fractional rate of protein synthesis was not changed i n sham-operated malnourished or well-nourished animals. During regener ation, protein synthesis in well-nourished animals was elevated compar ed to sham-operated controls, but a lesser stimulation was seen in mal nourished rats. It was concluded that the mechanism of liver regenerat ion depends on nutritional state, involving an increase in protein syn thesis in well-nourished animals, but relying more on a decrease in pr otein degradation or cessation of secretory protein synthesis in malno urished animals. (C) Journal of Hepatology.