Liver albumin synthesis in sepsis in the rat: influence of parenteral nutrition, glutamine and growth hormone

Abstract

The effect of sepsis on liver synthesis of albumin remains controversial, with studies in man suggesting that synthesis increases, whereas in animals increased, decreased and unaltered synthesis have been reported. To reconcile these conflicting data, total and relative albumin synthesis was measured in rats 24 h after caecal ligation and puncture (CLP) by immunoprecipitation of albumin following a flooding dose of L-[4-3H]phenylalanine. Following CLP, animals were starved for 18 h and then received intravenous infusions of saline or parenteral nutrition (PN) with or without glutamine for 6 h. In animals receiving PN, parenteral injections of growth hormone (GH) or saline vehicle were also administered. Fractional rate of liver total protein synthesis was elevated and total albumin synthesis rate was reduced in all CLP groups when compared with non-operated animals. Total albumin synthesis was also lower in all animals receiving PN than those receiving saline alone, although these differences did not attain statistical significance, except for the group receiving PN+GH. Relative albumin synthesis was also reduced after CLP, and was significantly lower in animals receiving PN than in those receiving saline alone. These findings suggest that in sepsis hepatic protein synthesis is reprioritized away from the production of albumin towards the production of acute-phase proteins and that this change is not influenced by the provision of nutritional support, glutamine or the administration of GH.