Reproducibility of gas chromatography-mass spectrometry measurements of 2H labeling of water: application for measuring body composition in mice.

Deuterium-labeled water (2H2O) has emerged as a novel isotope tracer. Following the administration of 2H2O, it is possible to study the dynamics of carbohydrate, protein, lipid, and DNA and to determine body composition. Those studies require reliable measurements of the 2H labeling of water.

Using isotope tracers to study metabolism: application in mouse models.

The application of isotope tracers for investigating metabolism in mice is discussed. To familiarize the reader, some basic principles regarding the use of tracer methods are outlined. Emphasis is placed on showing how investigators are using isotope tracers to study the regulation of carbohydrate, fat and/or protein turnover in vivo.

Influence of diet on the modeling of adipose tissue triglycerides during growth.

We have studied the accretion of lipids in growing mice. We measured the rates of synthesis and degradation of triglycerides in epididymal fat pads of mice maintained for 44 days on a low-fat, high-carbohydrate diet (I) or a high-fat, low-carbohydrate diet (II). 2H2O was added to the drinking water for 14 days.

Measuring gluconeogenesis using a low dose of 2H2O: advantage of isotope fractionation during gas chromatography.

The contribution of gluconeogenesis to glucose production can be measured by enriching body water with (2)H(2)O to approximately 0.5% (2)H and determining the ratio of (2)H that is bound to carbon-5 vs. carbon-2 of blood glucose.

Gas chromatography-mass spectrometry assay of the (18)o enrichment of water as trimethyl phosphate.

We have developed an assay for determining the 18O enrichment of water in biological fluids. Urine, plasma, or whole blood is reacted with phosphorous pentachloride to yield phosphoric acid. Derivatization of phosphoric acid with diazomethane generates trimethyl phosphate.