COMPARATIVE STUDY OF GLUCOSE AND FRUCTOSE METABOLISM IN INFANTS WITH REFERENCE TO UTILIZATION AND TO THE ACCUMULATION OF GLYCOLYTIC INTERMEDIATES1

Abstract

Infusions of glucose and fructose with electrolytes to three infants at a rate approximately 1 g per kg per hour resulted in essentially complete utilization of both sugars. Infusions of the sugars at a rate of approximately 2 g per kg per hour in eight subjects resulted in a significantly greater urinary loss of sugar with glucose (20% of intake) than with fructose (9.9%) (p < 0.02). The average urinary sodium excretion associated with glucose infusion was 79% of intake, which is significantly lower than that noted with fructose, 127% (p < 0.01) but no significant differences in water and potassium excretions were noted. Significant increases in pulse and respiratory rates and liver size occurred during fructose infusion in these subjects. These changes together with the finding of severe metabolic acidosis in one subject led to further investigation of the mechanism of these observations. Infusions of fructose solution with electrolytes to seven additional infants at the rate of 2g per kg per hour were accompanied by mean increases in whole blood lactate of 35.6 mg %, and in pyruvate of 2.16 mg %. Smaller increases occurred with glucose in eight subjects. Decreases in blood pH up to 0.22 and mean decreases in whole blood CO2 of 6.8 m[image] per 1 and in plasma sodium of 14 meq per 1 were demonstrated in the group of individuals receiving fructose. Significantly smaller changes were seen in these blood levels during glucose infusion. Mean lactic acid excretion during the period of infusion was 10.4 mg per kg per hour in the subjects receiving fructose, but only 0.6 mg per kg per hour in these receiving glucose. It is suggested that the advantage in fructose utilization over glucose, when administered at a rapid rate of infusion, may be offset by the induced metabolic acidosis and its attendant side effects.