Figure 2.

Excess dietary iron increases lipid utilization, lipid mobilization and wasting of fat energy stores

Six-week old C57BL/6 males were provided control (CID) or 2% carbonyl iron diet (IRD) for 3, 6, or 9 days

(A and B) Ex vivo lipolysis assay measuring glycerol and free fatty acids (FFA) released from (A) IWAT (B) and GWAT. Data shown represents one independent experiment (n = 5 mice per group).

(C) Body composition analyses using EchoMRI of mice fed CID or IRD for 6 days. Fat and lean mass were normalized to original body mass. Data shown represents two pooled independent experiments (n = 11 mice per group).

(D–F) Tissue masses of (D) IWAT (E) GWAT and (F) MWAT from mice fed CID or IRD for 6 days. Data shown for D,E represents two pooled independent experiments (n = 10 mice per group). Data shown for F represents one independent experiment (n = 5 mice per group).

(G) Muscle masses from hindlimb of mice fed CID or IRD for 8 days (Quadricep; Quad, tibialis anterior; TA, extensor digitorum longus; EDL, soleus, and gastrocnemius; Gastro). Data shown represents one independent experiment (n = 5 mice per group).

(H) Gene expression in gastrocnemius of mice fed CID or IRD for 8 days. Gene expression was normalized to housekeeping expression of Rps17. Data shown represents one independent experiment (n = 4 mice per group).

(I–K) Mice were housed in the CLAMS and given CID or IRD. The respiratory exchange ratio over the course of the experiment was determined. (I) Principal component analysis for the respiratory exchange ratio (RER) of CID and IRD fed mice in light/dark cycles. Ellipses are indicative of 95% confidence intervals. Data shown represents analyses of one independent experiment (n = 6 mice per group). (J) Average hourly respiratory exchange ratio of mice fed CID or IRD (RER) calculated as ratio of ml CO₂ OUT (respired):ml O₂ IN (inhaled). Data shown represents one independent experiment (n = 6 mice per group). (K) Area under the curve analysis for RER for periods of matched food consumption.

(L) Circulating levels of glycerol and FFA in serum of fasted CID or IRD mice on days 3, 6, and 9 of diet time course. Data shown represents one independent experiment (n = 5 mice per group).

(M) Intraperitoneal lipid tolerance test (i.p. LTT) performed on fasted mice fed CID or IRD for nine days. Data shown represents one independent experiment (n = 5 mice per group). Data represent mean ± SEM; ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, ∗∗∗∗p < 0.0001. Related to Figure S2.