Figure 3.

Fasting during the light photoperiod induces a hyper-glycemia and hyper-metabolic response.A–F) Recordings of chow fed and 4-h fasted mice. Left/green: ad libitum fed mice; center/blue: the same animals two days later fasted at 8 AM (arrow). Right: mean values for each animal between 0800 and 0900. A) blood glucose, B) body temperature, C) metabolic rate (energy expenditure), D) respiratory exchange ratio, E) in-cage physical activity (distance traveled) F) energy intake. The solid black line represents the mean value at each minute, the shaded area represents ± SEM, n = 11 male mice. G) A heatmap of position within the cage for one mouse from 0800 to 0900 under fasted or ad libitum conditions. The plotted area represents the physical location within the cage; height and color represent the accumulated time spent at each location. The food hopper is located in the top right corner. H–J) Estimates of glycemic variability including H) Continuous Overall Net Glycemic Action (CONGA), I) Mean Amplitude of Glycemic excursions (MAGE), J) Mean Absolute Deviation (MAD). K) Fasting induced corticosterone levels. L) Measurements of glucose before and after food removal with a hand-held glucometer (n = 20 male mice). ns, not significant; ∗p < 0.05; ∗∗p < 0.01; ∗∗∗p < 0.001.