Optical emission spectroscopy is a convenient method for determing 15N specific activity in a variety of metabolites following the administration of an 15N-labeled amino acid to humans. The only disadvantage, compared to the more conventional isotope ratio mass spectrometer analytical system is that more tracer is needed to give accurate results. When an 15N-labeled amino acid is used as the 15N carrier, the amount of 15N is not above a tracer dose. A suitable procedure is described for performing such studies using [15N]glycine as a tracer. As an experimental example, [15N]glycine was infused into a subject at a rate of 35 mg of N/hr for 8 hr. After 3 hr a meal was consumed by the subject. The urinary urea-15N, ammonia-15N and amino acid-15N profiles were determined.
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology