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Circadian Rhythm: The Molecular Clock

Circadian Rhythm: The Molecular Clock

MorningCortisol surges to wake you up and prime your body for the day ahead12AM3AM6AM9AM12PM3PM6PM9PMSCNMaster ClockCortisol peakWakefulness signalTestosterone peakLight (melanopsin)SCN
Morning sunlight triggers your cortisol peak, giving you energy and focus. This is your body's natural alarm clock.
Getting sunlight within 30-60 minutes of waking anchors this rhythm for the entire day.
Cortisol
Melatonin
Core body temperature
Growth hormone
Immune activity
Testosterone

分子フィードバックループ: CLOCK+BMAL1 -> Eボックス -> PER/CRY転写 -> PER/CRYタンパク質が蓄積してCLOCK/BMAL1を阻害 -> ループが約24時間ごとにリセット。視交叉上核(SCN)による光リセット経路と末梢時計の同期化も示されている。

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