[The effect of the nutritional status of rats on the protein biosynthetic activity in a cell-free system]

The recent paper deals with the influence of nutritional situation on the ability of cell sap fractions of liver and muscle of rats to stimulate protein biosynthesis in a cell-free system. The incorporation of 3H-leucine into polypeptides from tissues of ad libitum fed rats was 1.25-1.46 fold higher in the liver resp. 1.2-1.7 fold higher in the muscle in comparison to the incorporation data of the starved rats. Significant differences were also shown in the course of translation (incorporation of amino acids in dependence of concentration and time). The amino acid incorporation of starved animals rapidly reached a plateau at a low level of incorporation (liver 40,000 dpm, muscle 9,000 dpm) whereas at higher cell sap concentrations and prolonged times of incubation (120 min) degradation effects (proteolysis) must be taken into account. The incorporation of amino acids in tissues of ad libitum fed animals has still increased under the same conditions (liver 55,000 dpm, muscle 16,000 dpm). These results obtained with in-vitro-methods confirm findings got with in-vivo-techniques and may complete the investigations of protein metabolism sensibly.