Fig. 2.

Cytokine effects on Dbp, Per1, Per2, and Per3 in NIH 3T3 fibroblasts. Confluent cells were synchronized with 50% horse serum for 2 h (ZT 0–2). After serum shock, cells were kept in serum-free medium with TNF-α (10 ng/ml), IL-1β (10 ng/ml), IL-6 (10 ng/ml), IFN-α (10 ng/ml), IFN-γ (20 ng/ml) or without cytokines and analyzed at ZT 24 with quantitative real-time RT-PCR. Results are shown as percent of expression to noncytokine-treated fibroblast cultures; one representative experiment of three; mean values of triplicates ± SD; independent sample t test; *, P ≤ 0,05; **, P ≤ 0,005; ***, P ≤ 0.0005.