¹H NMR spectra of glucose metabolites in B cells. B cells were cultured in medium containing 10 mM [1-¹³C]glucose in the absence (A) or presence (B) of 10 μg/mL anti-Ig for 8 hours. Cells were then analyzed by 1D-HMQC as described in “Materials and methods.” The ¹³C from the [1-¹³C]glucose is metabolized to the lactate methyl group and the glutamate methylenes. (C-D) Incorporation of [1-¹³C]glucose into the lactate methyl group (▪) and the glutamate C⁴H₂ (•) and C³H₂ (○) pools in anti-Ig–stimulated B cells. (C) Integrated intensity of protons coupled to ¹³C selected in a 1D-HMQC experiment. (D) Specific ¹³C content of lactate and glutamate pools as a function of time after BCR crosslinking. (E) Incorporation of [1-¹³C]glucose into metabolites in B cells after BCR crosslinking (8 hours) in the absence (control) and presence of pretreatment (30 minutes) with 10 μM LY294002 (+LY), 50 nM wortmannin (+wort), or 20 nM rapamycin (+rap). The increases in ¹³C content (compared with the same metabolites in quiescent B cells where ¹³C content is 1.0) are shown for the lactate methyl group (black bars) and glutamate methylenes (open bars) (the average increase in ¹³C uptake into each glutamate methylene carbon is shown) and the citrate methylenes (gray bars) as a control. (F) ¹³C glucose incorporation and metabolism into lactate in response to anti-Ig stimulation of B cells at the indicated times (h); [1-¹³C]glucose labeling of the methyl group (•); [2-¹³C]glucose labeling of methyl (▪) and methine groups (○). (G) Fraction of lactate generated by the pentose phosphate pathway based on ¹³C label distribution in the CH₃ group as a function of time after anti-Ig stimulation of B cells incubated with [2-¹³C]glucose. Integration scales in each type of spectrum are arbitrary.