Fig 4. Peripheral organs of Clock^-/- mice can exhibit circadian rhythms in vitro.

(A) Two representative mPer2^Luc bioluminescence rhythms of rhythmic organotypic liver (black), lung (blue), kidney (red), and adrenal (green) slice cultures from wild type (left) and Clock^-/- (right) mice. After ~7 culture days, samples were treated with 10 μM forskolin (arrow). Y-axis scales are adjusted to amplitudes for better visualization of data. (B) Circadian mPer2^Luc rhythm period, amplitude, damping constant (days to reach 1/e of initial amplitude), and phase of first peak after forskolin treatment, and % of slices from wild type (unfilled bars) and Clock^-/- mice (filled bars) that were significantly rhythmic after forskolin treatment (culture days 8–14). Data are shown as mean ± SEM; *p≤0.05, **p≤0.01, ***p≤0.001 (student’s t-test); or % of slices rhythmic; n = 8.