Development of a New Technique for the Deterimination of Gluconeogenesis in Man by in Vitro NMR

Research project P 13718 Determination of Gluconeogenesis by Deuterium NMR Ernst HASLINGER 11.10.1999 Glucogenolysis and glyconeogenesis are two important metabolic pathways which contribute to the endogenous glucose production. The objective of the proposed research is to develop a fast and reliable method for the quantitative determination of the relative percentage of glycogenolysis and gluconeogenesis and thus will yield detailed information about glucose metabolism in man. The basic idea is that deuterium incorporation into different positions of glucose allows tracing of the metabolic pathways contributing to the pool of blood glucose. The principle of the proposed method relies on the ingestion of drinking water, containing a defined amount of H2O in order to achieve small body water enrichments. After drawing blood samples H NMR will be used to determine the site specific enrichment of blood glucose by integration of the particular deuterium resonances. This procedure will provide more information in less time compared with the techniques used today.

Glucose is the main source of energy for all cells in the human body. A constant concentration of glucose in the blood is therefore essential. Important metabolic pathways are glycogenolysis in the liver and gluconeogenesis (GNG). Both are continuously synthesising and releasing glucose into plasma. Determination of the relative contribution of these two pathways will give information about the mechanism of antidiabetic drugs or the influence of certain diets on the carbohydrate metabolism. Humans who drink water, enriched with deuterium, incorporate deuterium in the bloodglucose during GNG. Glucose was isolated from their blood plasma and the deuterium incorporation was measured by deuterium NMR yielding information about the relation of GNG vs. glycogenolysis. It is a new and powerful approach to determine GNG in humans and will give us information about the influence of nutrition on the carbohydrate metabolism and will also lead to an evaluation of the treatment of diabetes mellitus.