Impaired expression of clock genes in livers of TNF-α-infused mice. Animals were entrained to a LD cycle during 2 weeks, and their locomotor activity was constantly monitored via a passive infrared sensor and a running wheel. Mice were then implanted with osmotic minipumps delivering TNF-α (light gray bars) or saline as control (dark gray bars). On the third day after the operation, mice were killed at ZT = 11.5 or = 15.5 (ZT = 0, light on; ZT = 12, light off). Livers were extracted and gene expression assessed by real-time PCR. (A) Per1/2/3, RevErbα, and PAR bZip family genes, Dbp, Hlf, and Tef, are down-regulated at both time points, the suppression of PAR bZip family genes is highly significant. In contrast to fibroblast data, RevErbα is strongly down-regulated. Results are shown as percentages relative to the mean of the control group. One representative experiment of three is shown (n = 6 per group; Mann–Whitney test. *, P ≤ 0,05; **, P ≤ 0,005.)