Figure 3. In fed mice, in all tissues except brain and muscle, glucose labels TCA intermediates mostly through circulating lactate.

a, Turnover fluxes of glucose, lactate, and glutamine in fed and fasted mice (fed state: n = 5 for glucose, n = 12 for lactate, and n = 6 for glutamine; fasting state: n = 22 for glucose, n = 24 for lactate, and n = 5 for glutamine). Data are mean ± s.d., ****P < 0.0001; **P < 0.002 by t-test. b, Normalized labelling of TCA intermediates by ¹³C-glucose versus ¹³C-lactate, as in Fig. 2d, in fed mice. Data are from Extended Data Fig. 8. c, Direct circulating nutrient contributions to the tissue TCA cycle in fed mice; data are mean ± s.e.m. d, Steady-state whole-body flux model, as in Fig. 2f, in fed mice; data are mean ± s.e.m.