Figure 4.
Regulation of diurnal glucose homeostasis in rats exposed to LD or LL fed either regular chow or HFD. A, Diurnal profiles in plasma glucose (A), insulin (B), and calculated index of β-cell function HOMAβ (C) in rats fed either chow or HFD and exposed to 10 weeks of either standard LD (left) or LL (middle) light conditions. Bar graphs (right) display mean ± SEM of AUC for measures of plasma glucose (A), insulin (B), and HOMAβ (C) across the 24-hour day in rats exposed for 10 weeks to LD-Chow, LD-HFD, LL-Chow, or LL-HFD. Plasma samples were obtained at 6-hour intervals and P values in each graph represent statistical effects of “time” and “diet” interaction for each variable under LD and LL conditions derived from repeated measures two-way ANOVA analysis (GraphPad Prism v.6.0). *, P < .05 vs LD-Chow, LL-Chow, and LD-HFD; †, P < .05 vs LD-Chow; ‡, P < .05 vs LD-Chow and LL-HFD.