Summary
This review explains how the circadian clock, centered in the SCN and entrained by light, drives the diurnal rhythm of glucocorticoid secretion via the HPA axis and autonomic nervous system. For lighting designers and healthcare practitioners, this underscores that light timing affects not just melatonin but also cortisol rhythms, with broad implications for metabolic health, stress response, and synchronization of peripheral tissues.
Key Findings
- Glucocorticoid peak secretion is timed to the onset of the activity phase, controlled by the SCN acting through both the HPA axis and the autonomic nervous system.
- The adrenal gland contains its own circadian clock that modulates sensitivity to ACTH, adding a peripheral layer of circadian regulation independent of central SCN signaling.
- Rhythmically released glucocorticoids serve as systemic timing signals that help synchronize cell-autonomous clocks in peripheral tissues throughout the body.
Categories
Sleep & Circadian Health: Describes the circadian clock mechanisms controlling diurnal glucocorticoid release, relevant to understanding light-driven circadian entrainment and its downstream hormonal effects.
The Science of Light: Provides mechanistic context for how the suprachiasmatic nucleus (SCN), the primary light-entrainable pacemaker, regulates peripheral clocks via glucocorticoid signaling.
Author(s)
K Tejkal
Publication Year
2013
Related Publications
Sleep & Circadian Health
- Phototransduction by retinal ganglion cells that set the circadian clock
- The mammalian circadian timing system: organization and coordination of central and peripheral clocks
- The twoāprocess model of sleep regulation: a reappraisal
- Melanopsin is required for non-image-forming photic responses in blind mice
- Strange vision: ganglion cells as circadian photoreceptors
The Science of Light
- Phototransduction by retinal ganglion cells that set the circadian clock
- Color appearance models
- The mammalian circadian timing system: organization and coordination of central and peripheral clocks
- Diminished pupillary light reflex at high irradiances in melanopsin-knockout mice
- Melanopsin is required for non-image-forming photic responses in blind mice