Fatty Acid and Glycerol Kinetics in Septic Patients and in Patients with Gastrointestinal Cancer

The rates of glycerol and free fatty acid (FFA) kinetics in normal volunteers (VOL), non-weight-losing (NWL) gastrointestinal cancer patients, weight-losing (WL) gastrointestinal cancer patients, and in severely septic patients, using constant infusions of d-glycerol and 1-13C palmitic acid; were determined. Rates of FFA oxidation have also been quantitated. Measurements were made in the basal state, during glucose infusion (4 mg/kg/min), and during total parenteral nutrition (TPN). Rates of glycerol and FFA appearance (Ra) in volunteers and NWL cancer patients were similar, and in both groups there was a significant suppression after glucose infusion. The basal Ra values for glycerol and FFA were 2.4 +/- 0.2 and 6.5 +/- 0.8 mumol/kg/min, respectively, in the volunteers, and in the NWL cancer patients the corresponding values were 2.7 +/- 0.4 and 7.1 +/- 1.1 mumol/kg/min (not significantly different). Compared with the volunteers, the rates of glycerol and FFA turnover were significantly elevated in both septic patients and WL cancer patients. The values for glycerol and FFA Ra were 6.3 +/- 1.1 and 13.1 +/- 3.0 mumol/kg/min, respectively, in the septic patients. The corresponding values were 4.1 +/- 0.4 and 11.7 +/- 1.6 mumol/kg/min in the WL cancer patients. In contrast to the response seen in the volunteers and NWL cancer patients, glucose infusion did not suppress lipolysis in either the septic or WL cancer patients. In all groups studied, glucose infusion resulted in an increase in FFA recycling. Despite the fact that the WL cancer patients had an increased FFA availability, they were significantly less able to oxidize either endogenous FFA or infused lipid when compared with NWL cancer patients (the basal % of FFA uptake oxidized in WL cancer patients was 10 +/- 2% vs. 18 +/- 3% in NWL cancer patients). In contrast, the septic patients had an enhanced capacity to oxidize either endogenous FFA or infused lipid (the basal % of FFA uptake oxidized was 40 +/- 8%, and during TPN this increased in 65 +/- 10%). From these studies the following was concluded: in terms of lipid kinetics, NWL cancer patients are not significantly different from volunteers; WL cancer patients and septic patients have elevated rates of lipolysis, and in contrast to what was seen in NWL cancer patients and in volunteers, glucose infusion in WL cancer patients and in septic patients does not result in a significant inhibition of lipolysis; and WL cancer patients have an impaired capacity to oxidize either endogenous FFA or infused lipid.(ABSTRACT TRUNCATED AT 400 WORDS)