Changes in daily gene activity in rat pineal glands after switching the light/dark cycle using a full day of light or darkness

The resynchronization of the SCN-driven gene AANAT was nearly complete in three days after light-dark reversal.

• The resetting of clock gene expression in the rat pineal gland varies depending on whether the light-dark reversal occurs during a light or dark period.
• Clock genes exhibit gene-specific phase-shift modes and differential phase-shift rates after light-dark transitions.
• The resetting processes for clock genes were longer when the reversal was initiated by a light period compared to a dark period.
• Among the clock genes studied, Per1 adjusted most rapidly, while Cry1 adjusted most slowly after the light-dark reversals.

Simplified