Effects of portacaval anastomosis on liver and brain protein synthesis in rats

In vivo and in vitro protein synthesis was measured in livers from rats 3 weeks after a portacaval shunt (PCS) operation. A marked reduction in protein synthesis was observed, amounting to a 66 and 47% of inhibition, respectively. Above-saturation levels of amino acids were used in both conditions. The level of free exogenous amino acid was elevated consistently in the PCS animals 1 hour after isotope injection. In support of the data on liver protein synthesis, the incorporated radioactivity in serum proteins was reduced markedly. Heart muscle protein synthesis was unchanged while brain protein synthesis was inhibited when assayed in vivo. Neuronal cells showed a more marked inhibition of protein synthesis than did glial cells.