CARBOHYDRATE-INDUCED THERMOGENESIS IN LIVER-CIRRHOSIS - GLUCOSE VS FRUCTOSE

Reduced thermic response after a glucose load has been reported in liv er cirrhosis. To determine the mechanism and the site of this phenomen on, the effects of glucose and fructose on energy expenditure (EE) wer e measured in seven well-nourished cirrhotic patients and in six healt hy control subjects. EE and fuel utilization were measured via indirec t calorimetry for 3 h after oral glucose or fructose administration (1 g/kg body wt). After a glucose load, plasma glucose and insulin conce ntrations were higher in cirrhotic patients than in control subjects ( p < 0.05). During the glucose trial, the cumulative incremental change s in EE over the 3-h measurement period were lower (p < 0.01) in patie nts than in the control subjects (0.98 +/- 0.13 vs. 1.70 +/- 0.23 kJ . kg(-1) . 3 h(-1)). After fructose ingestion, the cumulative changes i n the EE of control subjects (1.76 +/- 0.24 k . kg(-1) . 3 h(-1)) and cirrhotic patients (1.59 +/- 0.15 kJ . kg(-1) . 3 h(-1)) were similar. In cirrhotic patients, the EE increase after fructose was higher than after glucose (p < 0.05). After glucose and fructose ingestion, no di fference was observed between the carbohydrate oxidation in cirrhotic patients and that in control subjects, and lipid oxidation was suppres sed to the same extent in both groups. We conclude that glucose-induce d thermogenesis is impaired in liver cirrhosis, whereas fructose can n ormalize the thermic response. Because fructose is chiefly metabolized in the liver, these findings suggest that extrahepatic tissues are th e site of defective thermogenesis in liver cirrhosis.