Stable - Isotope Gas Analyzer

Measure the oxidation of exogenous nutrients

Figure A shows the oxidative disposal of a 2.5 mg bolus of ¹³C-glucose in a control mouse.  Possible experimental manipulations include: age, diet, hormonal treatment, experimental drugs, microbiome manipulations, exercise, thermal exposure, surgical procedures, illness/injury, etc.  Critical metrics include magnitude and duration of response and AUC for calculating % dose recovery.

Measure the oxidation of endogenous nutrients

Figure B shows the oxidation of a fatty acid tracer (¹³C-Palmitic acid) infused into rodent diet for 10 days, selectively enriching the body lipids with ¹³C.  The CO₂ and δ¹³C measured during rest, treadmill exercise (15 m/min) and recovery show that total lipid oxidation of a mouse increases during the first minute of exercise, but decreases to resting levels during steady-state exercise.  Researchers could also selectively enrich the proteins in the body by feeding rodent diet infused with ¹³C-1-L-Leucine, thereby allowing quantitative assessment of endogenous protein oxidation in real-time.