Measuring body clocks in living mice

Circadian oscillations were detected in the kidney, liver, and submandibular gland of about half of the SCN-lesioned, behaviorally arrhythmic mice.

• The SCN is traditionally believed to regulate circadian rhythms, but peripheral tissues can exhibit independent oscillations.
• In vivo measurements show that circadian rhythms in certain organs persist even after SCN lesions.
• The amplitude of circadian oscillations in the kidney, liver, and submandibular gland was reduced in SCN-lesioned mice.
• Free-running periods of peripheral clocks matched the activity rhythms observed prior to SCN lesions.

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