Exchange of free fatty acids and glucose in leg tissues before and immediately after surgery.

The present study was undertaken to investigate whether there is an augmented uptake of free fatty acids (FFA) in the leg tissues immediately after surgery when the energy expenditure of the leg is increased considerably. Eight patients were studied before and after cholecystectomy. Blood and plasma flow were determined in one leg, as well as arterio-venous concentration differences for oxygen, glycose, lactate and the total fraction of FFA. To determine uptake and release of FFA, 1-(14C)-oleic acid was infused intravenously and the arterio-venous differences for (14C)-FFA were determined. The mean oxygen uptake in the leg increased from 0.72+/-0.06 mmol/min to 1.78+/-0.41 mmol/min. The uptake of free fatty acids in the leg did not increase significantly after cholecystectomy when compared to before operation in spite of the marked increase in oxygen uptake. Postoperatively there was, however, a positive linear relationship between the uptake of FFA and that of oxygen in the leg. The glucose uptake, after correction for released lactate, corresponded to 7% of the oxygen uptake before surgery and 13% after surgery. The arterial FFA concentration did not change. This study indicates that the combined possible contribution of glucose and free fatty acids to the oxidative energy metabolism of the leg tissues exceeded the oxygen uptake before, but not after surgery. In the postoperative state there was a positive correlation between oxygen uptake and FFA uptake in the leg.