Abstract
It has already been made clear that, the rise in blood glucose after glucose infusion was higher than that of fructose following its administration. On the other hand, it has also been reported that the rise in lactate, pyruvate, a-ketoglutarate in the blood and the plasma citric acid following fructose administration is much higher and more rapid when compared with the case of glucose administration. In every case of these reports, however, infusions were given in a fairly large amount over a fairly long period of time, but not in a dose commonly administered for therapeutic purposes. Therefore, the author observed the fluctuation in the concentration of citric acid, calcium and inorganic phosphate in the blood serum after the injection of a dose routinely used for therapeutic purposes was given to healthy persons, thereby attempted to investigate the difference of these two sugars in their metabolic pathway. The following is the results thus obtained.
1. The rise in the serum citric acid following fructose injection was found higher than that of glucose injection and fall to the normal level 2 hours after the injection whereas following glucose injection the drop of serum citric acid below the normal level was ofsewed 2 hours after injection.
2. The drop in the level of inorganic phosphate in the blood serum was observed following either fructose or glucose injection, though the drop followed fructose injection was found smaller and more rapidly reached to the normal level. However, in the case of glucose injection, no tendency of recovering the level prior to the injection was noted even 2 hours after the injection.
3. The fluctuation in the concentration of calcium in the blood serum after fructose or glucose injection did not demonstrate any significant difference from that in the untreated cases.
From the above difference in the fluctuations of the citric acid and inorganic phosphate in the blood serum after the injection of these two sugars, and also from the fluctuations of the concentrations of blood pyruvate, lactate and a-ketoglutarate which were reported by earlier workers, the presence of a qualitative difference between fructose and glucose in their metabolic pathway was infered.
