Summary
This thesis explores how glucocorticoids, which exhibit a pronounced diurnal rhythm, act as entraining signals from the SCN to peripheral tissues such as the hippocampus and colon, coordinating clock gene expression across the body. Understanding glucocorticoid-mediated entrainment informs how light-dark cycle disruptions (e.g., shift work, irregular light exposure) propagate metabolic and circadian dysregulation through hormonal pathways.
Key Findings
- Adrenalectomy (removal of glucocorticoid signaling) altered clock gene expression in peripheral clocks (hippocampus, distal colon) but effects on the central SCN clock were also examined, suggesting differential dependency on glucocorticoid signals.
- Restricted feeding time, which also modulates glucocorticoid levels, showed comparable effects to adrenalectomy on peripheral clock gene expression, highlighting the interplay between feeding schedules and hormonal circadian entrainment.
- Glucocorticoid receptor (GR) activity modulation via synthetic GR ligands demonstrated that GR signaling dynamics are a key mechanism by which the circadian system coordinates peripheral tissue rhythms.
Categories
Sleep & Circadian Health: Examines glucocorticoid signaling as a key mechanism for entraining peripheral circadian clocks, with direct relevance to understanding light-driven circadian regulation.
The Science of Light: Investigates suprachiasmatic nucleus (SCN) clock gene expression and the role of glucocorticoids as output signals from the central circadian pacemaker to peripheral tissues.
Author(s)
K Tejkal
Publication Year
2015
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 two‐process 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