It has been known for some time that the administration of glucose to dogs or normal human subjects leads to an increase in the pyruvate concentration and a decrease in the level of inorganic phosphate in the blood. These changes also occur when a diabetic patient receiving insulin is given glucose. The increase in the blood pyruvate, coupled with a decrease in inorganic phosphate content, has been used as an index of the metabolism of administered sugar.
Recently, a series of studies1 on the metabolism of intravenously administered fructose in normal and diabetic subjects has been reported. The changes in the blood concentration of fructose, pyruvate, and inorganic phosphate following an intravenous injection of fructose indicates to these investigators that the metabolism of fructose is different from that of glucose in both normal subjects and diabetic subjects without insulin. After giving fructose to either group there is an increase