Figure 2:

A) Concept of Mass Spectroscopy to Assess the Glycolytic Pathway Intermediates ¹³C-labeled glucose tracing strategy. Isotopically labeled ¹³C carbons (grey) can be distinguished from naturally occurring ¹²C (open circles) by mass spectrometry. The incorporation of [U-¹³C]glucose into unlabeled glucose pools is expressed as percent enrichment. 3PG-3-phosphoglycerate; PEP-phosphoenolpyruvate; OAA-oxaloacetate B) Results of Serum Glucose Enrichment with ¹³C Glucose Serum enrichment of glucose m+6 ([U-¹³C]) from the time of initial infusion. Data are expressed as average and SEM. Glucose m+6-represents the % of glucose molecules that all of the carbons in glucose are labeled ¹³C.