Description
Continuous measurement of 13C and 18O isotopes in exhaled breath
The new Stable Isotope Gas Analyzer is a cutting-edge upgrade to our standard Promethion™ systems, allowing simultaneous measurement of stable isotope tracers synchronously with the Promethion data stream.
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.
For more information on stable isotope labeling utilization, see:
McCue, M. D. (2011). “Tracking the oxidative and non-oxidative fates of isotopically labeled nutrients in animals.” BioScience 61(3): 217-230.
Welch Jr, K. C., et al. (2016). “Combining respirometry with stable isotopes to investigate fuel use in animals.” Annals of the New York Academy of Sciences 1365(1): 15-32.
McCue, M. D. and K. C. Welch Jr (2016). “13C-Breath testing in animals: Theory, applications, and future directions.” J Comp Physiol 186B(3): 265-285.