Lipolysis and lipid oxidation in weight-losing cancer patients and healthysubjects

increased lipolysis has been suggested as one of the possible mechanisms un derlying cancer cachexia, The study aim was to assess whether lipolysis is increased in weight-losing cancer patients, considering their differences i n food intake and body composition. Sixteen healthy subjects and 18 cancer patients with different tumor types and a weight loss of at least 5% in the previous 6 months were included in the study. Food intake was recorded for 4 days. After an overnight fast, [1,1,2,3,3-H-2(5)]glycerol was infused to determine the rate of appearance (Ra) of glycerol as a measure of whole-bo dy lipolysis, and [1-C-13]palmitic acid was infused to determine the Pa of palmitate as a measure of adipocyte fatty acid release, Palmitate oxidation was determined by measuring (CO2)-C-13 enrichment in breath samples, and b ody composition was measured by bioelectrical impedance analysis, After adj ustment for energy intake, whore-body lipolysis was significantly higher in cancer patients versus healthy subjects (6.46 +/- 0.63 and 4.67 +/- 0.46 ( mu mol/kg +/- min, respectively, P < .05). The difference in adipocyte fatt y acid release did not reach statistical significance. The rate of palmitat e oxidation was also significantly higher in patients than in healthy subje cts (1.15 +/- 0.10 and 0.93 +/- 0.07 mu mol/kg . min, respectively, P < .05 ). No differences in body composition were observed between groups. In conc lusion, whole-body lipolysis las measured by the Pa of glycerol) and palmit ate oxidation were elevated in weight-losing cancer patients, but fatty aci d release was not significantly different. Copyright (C) 2000 by W.B. Saund ers Company.