Comparison between the Intravenous and Oral Application of Glucose for Loading of the Carbohydrate‐Metabolism.

Abstract

Résumé. A loading‐test in which the sugar is administrated orally, subcutaneously or intramuscularly, is beset with considerable sources of error, of which variation in the rate of absorption is the principal one. The best loading‐test, therefore, will be the one by which the sugar is introduced intravenously. By the peroral loading‐tests no regard is paid — nor can be paid — to variations in the rate of resorption. After intravenous injection of 20 gr. of glucose during 3–4 minutes, the blood‐sugar curve in »normal» persons (i. e. non‐diabetics) presents the following characters: the blood‐sugar rises to 0.300% à 0.400% the fasting blood‐sugar concentration is re‐established in from 90 to 100 minutes. the area‐figure is rarely > 60 cm 2 . the loading‐figure is < 160. the blood‐sugar fall is continuous and fairly regular. after the re‐establishment of the blood‐sugar concentration, a consecutive hypoglycaemia sets in, and the blood‐sugar concentration may fall to values which are 20%‐30% below the fasting value. The advantages of the intravenous loading‐test are the following: when the sugar is introduced in this manner one has control of the time taken for introducing the sugar into the intermediary metabolism, and especially one knows at what instant the sugar introduction ceases, so that the blood‐sugar curve after intravenous injection of sugar only is an indication of the strength and range of the processes which tend to remove (eliminate) an excess of sugar from the blood. the quantitative expression for the blood‐sugar curve (the loading‐figure) varies less than the corresponding expression for the blood‐sugar curve after oral administration of glucose .