LIPOLYSIS DURING ABDOMINAL-SURGERY

Subcutaneous adipose tissue lipolysis has been monitored with microdia lysis during elective cholecystectomy by laparotomy in otherwise healt hy nonobese subjects. Eight of the subjects received saline and seven received glucose iv during the operation. In both groups the glycerol level in the microdialysate (lipolysis index) started to increase stea dily from the start of the general anesthesia until the abdominal wall was closed. Thereafter it leveled off and remained elevated until aft er extubation. Plasma glycerol started to rise after the surgical inci sion. The levels of noradrenaline and adrenaline, but not of insulin, glucagon, and cortisol in plasma, changed in parallel with that of gly cerol in the microdialysate. The glycerol response in adipose tissue i n the group receiving iv glucose was three times more marked than in t he saline group (P = 0.01) in spite of marked hyperinsulinemia, but th ere was no difference between the groups in plasma glycerol response. The plasma noradrenaline response was 50% higher (P = 0.03) in the glu cose group than in the saline group, but there was no difference betwe en the groups in the plasma adrenaline, glucagon, or cortisol response s. Adipose tissue blood flow was measured by the escape of ethanol fro m the dialysis solvent into the extracellular space. It was constant t hroughout the experimental period in both groups. In conclusion, the l ipolysis rate is accelerated during general anesthesia and abdominal s urgery because of increased catecholamine production. Perioperative gl ucose infusion is associated with a further acceleration of the lipoly tic rate in subcutaneous adipose tissue due to an additional activatio n of the sympathetic nervous activity that overrides the antilipolytic effect of the glucose-induced hyperinsulinemia. Other adipose regions may be less sensitive to glucose infusions and anesthesia.