Endotoxemia affects organ protein metabolism differently during prolonged feeding in pigs

The metabolic response after sepsis is characterized by net protein loss. N utritional intervention often Is applied to sustain whole body protein mass under such circumstances. The manner in which protein metabolism of the di fferent organs is affected under nutrition-supported and postseptic circums tances remains ambiguous. Therefore, we explored the changes in in vivo org an and whole body protein turnover after endotoxin-induced sepsis during en teral nutrition in pigs. The use of isotopes enabled simultaneous measureme nts of protein synthesis, breakdown and amino acid degradation across the p ortal-drained viscera (PDV; approximate to intestine), liver and hindquarte r ( approximate to 50% skeletal muscle). All pigs received a continuous ent eral infusion of a liquid meal equivalent to 0.3 g protein(.)kg bw-1 h (-1. ) 3 d before and 4 d after a 24-h endotoxemia period. Measurements were per formed 1 d before and 1 and 4 d after endotoxemia that was induced by a 24- h endotoxin (3 mug(.)kg bw(-1.)h(-1) lipopolysaccharide, n = 7) infusion. C ontrols received NaCl (n = 7). At 4 d after endotoxemia, hindquarter protei n turnover was increased, resulting in net synthesis. The amino acid output by the PDV was increased 1 and 4 d after endotoxemia. In the liver, net pr otein synthesis was enhanced 1 d after endotoxemia. Increased amino acid tr ansamination in hindquarter and PDV led to glutamine and alanine effluxes t hat serve as substrates for liver and, possibly, the immune system. By prov iding substrate, enteral nutrition can sustain elevated amino acid demand i n the postendotoxemic state by hindquarter, PDV and liver for protein synth esis and transamination processes.