[Oxygen, carbohydrate and fat metabolism of the splanchnic region under the influence of equimolecular parenteral doses of glucose and fructose].

Hepatic metabolic balances derived from arterio-hepatic venous substrate differences and hepatic blood flow exhibited similar results during fructose and glucose infusion (10 g/5 min, 0.5 g/kg X h) as compared to those from the isolated perfused organ. Accordingly, in account of hepatic utilization of fructose glucose homeostasis and secretion maintained during fructose infusion. However, the smaller insulin response during fructose infusion did not reduce hepatic free fatty acid utilization to such an extend as to increase pyruvate oxydation. Thus, splanchnic production of lactate and pyruvate descending from fructose was enhanced leading to a 7-fold increase of arterial lactate concentration. Since hepatic venous lactate to pyruvate substrate ratios did not change, the rise of the arterial redox couple could not be due to hepatic fructose metabolism. According to the findings from the isolated perfused organ, fructose seemed to be phosphorylated at a rate which was found to be 2-3-fold that of glucose as calculated from splanchnic utilization rates. The rapid ATP-breakdown was followed by an increment in splanchnic oxygen consumption. The larger energy demand during fructose infusion seemed to be satisfied by an enhanced endoxydation of free fatty acids.