High-Fat Diet Induces IKKβ and Reduces Insulin Sensitivity in Rats with Low Running Capacity

Abstract

Rats bred for a high-capacity to run (HCR) do not develop insulin resistance on a high-fat diet (HFD) vs. those bred for a low-capacity for running (LCR). Recently, a link between obesity and insulin resistance has been established via IKKβ action and IRS-1 Ser^312/307 phosphorylation. This study measured IκBα and IRS-1 pSer³⁰⁷ in mixed gastrocnemius muscle in HCR and LCR rats challenged with a 12-wk HFD. HFD treatment resulted in significantly higher glucose and insulin levels in LCR vs. HCR rats. IκBα levels, an inverse indicator of IKKβ activity, were lower in LCR vs. HCR rats maintained on chow diet and were reduced further following HFD in LCR rats only. IRS-1 pSer³⁰⁷ in the LCR rats increased on the HFD vs. chow. We conclude that differences in glucose tolerance between LCR and HCR rats are at least partly explained by differences in IKKβ activity and pSer³⁰⁷ levels.

Key words

aerobic capacity - IKKβ - insulin signaling - high-fat diet

References

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