Abstract
The pronounced influence which acids and alkalies exert on the rate at which glycogenase converts glycogen into reducing sugar has suggested the possibility that variations in the activity of this enzyme in the liver cells may depend primarily on changes occurring in the reaction (H-ion concentration) of the immediate environment in which the enzyme is acting. 1 Although there are now many facts which indicate that a condition of hyperglycemia (and glycosuria) usually develops when acids gain entry to the blood and that the opposite condition of hypoglycemia is readily induced with alkalies, yet there is no direct evidence that these changes in the reducing power of the blood are immediately dependent upon corresponding alterations in the rate of hepatic glycogenolysis in warm blooded animals.
A direct method for testing the influence of changes in reaction in the liver cells on the glycogenolytic process is offered in the experimental procedure which has recently been described by Pearce and Macleod. 2 Briefly, this consists in an estimation of the reducing power of the blood removed at short intervals (2-3 minutes) from the portal vein and vena cava inferior (opposite the entry of the hepatic veins), several consecutive estimations being made before, during and after the injection of a dextrose solution under constant pressure, into a branch of the mesenteric vein. When the percentage reducing power is equal in the two bloods, the glycogenolytic process in the liver is presumably dormant; when the percentage is higher in the vena cava than in the portal vein, glycogenolysis must be active; and when lower, the opposite (namely, a building up of glycogen out of the injected sugar) must be taking place. In previous investigations, in which neutral solutions were employed, no retention of dextrose by the liver could be demonstrated when about 0.5 gm. was injected into the portal circulation during five minutes.
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