Fig. 1.

Per1 Deficiency Uncouples Daily Energy Metabolic Rhythm from Behavior Oscillations. A, B) Analysis of feeding behavior (left), water intake (middle), and locomotor activity (right) of Per1^−/− (A) and WT (B) mice (n = 4 per group) fed ad libitum. Food consumption, water intake, and voluntary locomotor activity were recorded using metabolic cages. Locomotor activity is presented in arbitrary units (a.u.). C) Oxygen consumption (left), carbon dioxide production (middle) and respiratory exchange ratio (right) were measured for 24 h (n = 4). Male WT and Per1^−/− mice fed a ND at 8–10 weeks old were acclimated to the chambers for 4 days and recordings were performed for 2 days, yielding one full 24-h periods of data using metabolic cages. D, E) PCA scores plot (D) and color-coded loading plots (E) of OSC-PLS-DA for liver extracts obtained from WT mice (n = 9–10/time point, 8 weeks old). F, G) PCA scores plot (F) and color-coded loading plots (G) of OSC-PLS-DA for liver extracts obtained from Per1^−/− mice (n = 8/time point, 8 weeks old). Metabolites that contributed to group separation were then visualized and color-coded according to the absolute correlation coefficient of each variable with each group. Color coding is in accordance with the fold change in metabolites, where red indicates a significant change. Normalized values are shown in Table S1. Throughout, all data were expressed as the mean ± SEM and male mice for this experiment were maintained on standard chow. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)