Glucose infusion does not suppress increased lipolysis after abdominal surgery

The purpose of this study was to investigate the effect of glucose infusion on lipid metabolism after abdominal surgery. Patients (n = 6) with non-met astasized colorectal carcinoma were investigated on the second day after su rgery and healthy volunteers were studied after an overnight fast. The rate s of glycerol appearance (R-a glycerol), i.e., lipolysis rates, were assess ed by primed continuous infusion of [1,1,2,3,3, H-5(2)] glycerol before and after 3 h of glucose infusion (4 mg(.)kg(-1.)min(-1)). Plasma concentratio ns of glycerol, free fatty acids, glucose, lactate, insulin, and glucagon w ere determined. Fasting R-a glycerol was higher in patients than in volunte ers (7.7 +/- 1.8 versus 1.9 +/- 0.3 mu mol(.)kg(-1.)min(-1), P < 0.05). Glu cose infusion suppressed the R-a glycerol in volunteers to 1.0 +/- 0.2 <mu> mol(.)kg(-1.)min(-1) (P < 0.05), whereas lipolysis was not affected in-pati ents. Plasma concentrations of glycerol and free fatty acids similarly decr eased during glucose administration by 50% in both groups (P < 0.05). In co ntrast to the patients, a significant correlation (r = 0.78, P < 0.05) betw een the R-a glycerol and plasma glycerol concentration was observed in norm al subjects. The hyperglycemic response to glucose infusion was significant ly more pronounced (P < 0.05) In patients (10.7 +/- 0.7 mmol/L); than in vo lunteers (7.1 +/- 014 mmol/L, whereas the plasma insulin increased to the s ame extent in the two groups (P < 0.001). In conclusion, lipolysis rates ar e increased after abdominal surgery and glucose administration, most likely due to insulin resistance, and fail to inhibit stimulated whole-body lipol ysis. (C) Elsevier Science Inc. 2001.