Figure 2. Glucose is an important contributor of carbon substrate for the formation of lactate.

The mass isotopomer distribution of lactate after incubation of MM1S or RPMI-8226 human myeloma cell lines (HMCLs) in cell culture media containing either U[¹³C₅]Glutamine or U[¹³C₆]Glucose. The (m+3) isotopomers highlighted in green and red circles represent the isotopomer derived from U[¹³C₅]Glutamine and U[¹³C₆]Glucose, respectively. Bar graph values represent the averages of the individual data points (triplicates) that overlay the bar graph. The error bars represent ± SEM. Comparisons were made using the 2-tailed Student t test, and significance was defined as P < 0.05.