The influence of abdominal surgery on the splanchnic exchange of amino acids.

The splanchnic exchange of amino acids was studied during and immediately after elective cholecystectomy in 10 patients given a constant infusion of glucose (1.1 mmol/min). Measurements of splanchnic blood flow and arteriohepatic venous differences of plasma amino acids, glucose, lactate and glycerol were made preoperatively, intraoperatively and twice in the immediate postoperative period. The arterial plasma concentration of most amino acids declined during and after surgery but the arterial concentration of alanine was highest in the postoperative period. The total splanchnic uptake of amino acids increased from 140.3 +/- 36.0 mumol/min preoperatively to 338.2 +/- 51.7 mumol/min postoperatively (p less than 0.05). Alanine and glutamine accounted for 65-70% of the total splanchnic uptake of amino acids throughout the investigation. The fractional extraction of methionine increased in the immediate postoperative period, while the fractional extraction of the remaining amino acids was stable. The splanchnic uptake of gluconeogenic substrates exceeded the splanchnic glucose release. The splanchnic uptake of amino acids had already increased intraoperatively and further increased postoperatively despite a net splanchnic glucose uptake in this period.