Figure 5. Reverting obese females to a healthy diet prior to pregnancy does not restore oxidative capacity in fetal gastrocnemius.

(A) Respiratory flux (JO₂) adjusted according to muscle weight was measured after sequential addition of pyruvate/malate (P/M), ADP, glutamate (G), succinate (S), oligomycin (OMY) and the uncoupling agent carbonylcyanide p-trifluoromethoxy-phenylhydrazone (U) in permeabilized muscle fiber bundles (PMFBs) from male (circles) and female (triangles) fetal offspring of lean/overweight dams (n = 7) that had only received control diet (Ln/CTR), obese dams chronically fed a Western-style diet (Ob/WSD, n = 9), and obese dams chronically (≤ 9 years) fed a WSD before pregnancy but reverted to CTR diet prior to pregnancy (Ob/CTR, n = 5). (B) JO₂ was measured after sequential addition of palmitoylcarnitine and malate (FA), ADP, pyruvate (FA+P), G, S, U, and the complex I inhibitor rotenone (Rot) in PMFBs from Ln/CTR (n = 5), Ob/WSD (n = 8) and Ob/CTR (n = 4). (C) Electron transfer system (ETS) coupling efficiency was calculated as 1 – (CI + II_L) divided by the subsequent noncoupled ETS capacity during the pyruvate protocol. (D) Coupling control ratio was calculated as leak respiration in the presence of OMY (CI + II_L) divided by the preceding uninhibited oxidative phosphorylation flux (CI+II_P) during the pyruvate protocol. (E) Citrate synthase (CS) activity was measured in frozen tissues corresponding to the respirometry samples. Data were analyzed by 2-way ANOVA (maternal group × substrate) with Tukey post-hoc in A and B or 1-way ANOVA in C–E. Letters are used to indicate significant post-hoc differences (P < 0.05) between maternal groups. Groups with the same letter are not significantly different from each other. Individual data points and the group mean + SEM are shown.