(A–C) Quantitative PCR analysis in murine livers. Daily oscillations of Cyp2b10 expression (A) are abolished in Npy KOs compared to their background controls (wild type), while oscillations of the circadian gene, Reverb alpha (B), are unaffected. (C) Levels of another liver clock-independent gene, Alas1, are similar in wild type and Npy KO, suggesting Npy does not regulate its rhythmicity. For qPCR data, n=3–4 mice for each genotype and time point. Transcript levels were normalized to the housekeeping gene 36B4. (D–F) Microarray analysis was used to detect transcript expression in livers of Npy KO and their background controls collected over the course of 24 hr in LD. (D) The heatmap includes transcripts that oscillate in wild type but not in Npy KO liver. Data represent the average transcript abundance from n=2 samples for each genotype and timepoint. Here, the MetaCycle p-value cutoff of p<0.01 was used to identify cyclic transcripts; p>0.8 was considered not cyclic. (E) The median expression values of the wild type-only cyclic transcripts are not different between Npy KO and wild type. (F) Daily expression values of cytochrome P450 genes from microarrays. Cytochrome P450 genes Cyp2b10, Cyp2r1, Cyp17a1, and Cyp2c70 are cylic in wild type liver but are not cyclic in Npy KO liver. Cyp3a13 and Cyp7a1 cycle robustly in both wild type and Npy KO. Graphs show average ± SEM. ZT- Zeitgeber Time.