Strong syncing of body clocks by steroid hormone injections in genetically modified mice

Clock/Clock mice exhibited significantly decreased bioluminescence and peripheral clock rhythms compared to wild-type mice.

• Peripheral clocks in Clock/Clock mice showed decreased amplitudes and delayed phases.
• Daily injections of the synthetic glucocorticoid dexamethasone increased amplitudes and advanced phases in the peripheral clocks.
• T-cycle experiments indicated that the peripheral clocks in Clock/Clock mice synchronized to a 30-hour stimulation interval.
• The results suggest that DEX stimulation enhances the synchronization ability of peripheral clocks in Clock/Clock mice.
• Weak internal clock oscillators may contribute to the altered synchronization patterns observed in Clock/Clock mice.

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