Thedilution of the intracellular unlabeled TCA intermediate pool (i.e., [m+0] TCA intermediates) with theircorresponding 13C isotopomers is significantly higher in HMCLs incubated with U[13C5]Glutamine thanU[13C6]Glucose, which indicates a higher percentage of incorporation of glutamine into the TCA cycle viaanaplerosis compared with glucose entry into the TCA cycle via pyruvate.