Figure 4.

A, Glucose isotopomers and resultant fractional isotopomer contribution to the glucose pool (FC) as generated from TCAsim software using liver data from rats infused with [2,4,6,8-¹³C₄]octanoate for 105 min. Brain energy metabolism was modeled using an 80% glucose contribution (80% of FC) giving rise to acetyl-CoA populations as shown (Fc1, Fc2, Fc12, and Fc0). B, By combining 80% glucose contribution with 20% from exogenous [2,4,6,8-¹³C₄]octanoate, 100% of brain energy metabolism is accounted for (not different from steady-state analysis values in Table 1; p ≤ 0.01).