Figure 2.

Incorporation of CO₂ into several metabolites inside and outside of the cells. The vertical axis represents the relative fraction of ¹³C-labeled metabolites, which was calculated as follow as: m₁/ ${\displaystyle \sum _{i=0}^n{\mathit{m}}_i}$, where m₁ and m_i are the corrected intensities and n is the number of carbon atoms in metabolites (n = 3 in the case of lactate, for example). (a) Intracellular metabolites. (b) Extracellular metabolites. White and gray bars represent the ratios of each metabolite in media containing NaHCO₃, and NaH¹³CO₃, respectively. Error bars and asterisks indicate standard deviations and significant difference (*P < 0.01), respectively.