FIGURE 2.

A shift in metabolic channeling of dietary glucose occurs upon HSD feeding. A, proposed route of dietary glucose into lipid in larvae reared on control or chronic HS diets. Dietary [U-¹³C₆]glucose undergoes glycolysis and then enters the tricarboxylic acid cycle (TCA) to follow a metabolic route either directly (m + 2; solid line) or indirectly (m + 1; dotted line) into fatty acids. OAA, oxaloacetate; PEP, phosphoenolpyruvate; pyr, pyruvate; G-6-P, glucose 6-phosphate. This diagram is simplified, and some steps have been omitted. B–D, isotopomer composition (m + 2 or m + 1) of NEFA at 6 h (B) or TFA at 6 h (C) or TFA at 24 h (D) after transfer to labeled diets. Shown is the weighted average of 14-, 16-, and 18-carbon fatty acids. Error bars are ±S.E. The ratio of (m + 2)/(m + 1) for each condition is shown beneath the graphs. An unpaired, two-tailed t test was used to derive p values. ctl, control.