Gluconeogenesis and fasting in cerebral malaria.

BACKGROUND In healthy subjects after an overnight fast, glucose production is for approximately 50% derived from glycogenolysis. If the fast is prolonged, glucose production decreases due to a decline in glycogenolysis, while gluconeogenesis remains stable. In cerebral malaria, glucose production is completely derived from gluconeogenesis after an overnight fast. It is not known if glucose production also decreases during fasting when its only source is gluconeogenesis. DESIGN Glucose production was measured by infusion of [6,6-2H2]glucose in seven patients with cerebral malaria after prolonging a fast from 20.30 to 00.30 hours. RESULTS Glucose production decreased by approximately 10% (27.4 +/- 2.1 to 24.7 +/- 1.6 micromol/kg/min, p = 0.05), without changes in the plasma concentrations of glucoregulatory hormones, FFA or precursors. CONCLUSIONS In the patients with cerebral malaria, glucose production decreases during fasting due to a decrease in the rate of gluconeogenesis. These data suggest that the decrease in the rate of glucose production during short-term fasting is actively regulated and not simply due to shrinkage of glycogen content, as in the absence of glycogenolysis, glucose production decreases at the same rate as normally seen in healthy subjects whose glucose production is for approximately 50% derived from glycogen and in whom gluconeogenesis is stable.