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Related Experiment Video

Updated: May 25, 2026

Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures

Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures

Published on: November 11, 2016

The human circadian metabolome.

Robert Dallmann¹, Antoine U Viola, Leila Tarokh

¹Chronobiology and Sleep Research Group, Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland. dallmann@pharma.uzh.ch

Proceedings of the National Academy of Sciences of the United States of America

|February 7, 2012

Summary

The human body

Area of Science:

Chronobiology
Metabolomics
Human Physiology

Background:

The circadian clock regulates human physiology, and its disruption is linked to diseases like cancer and diabetes.
The relationship between the circadian clock and metabolism is complex, with ambiguity regarding direct clock control versus indirect influences from sleep-activity and feeding patterns.

Purpose of the Study:

To investigate whether metabolic changes are directly controlled by the endogenous circadian clock or influenced by external factors like sleep and feeding.
To identify specific metabolites regulated by the circadian clock in human plasma and saliva.

Main Methods:

An unbiased metabolomic screen of human plasma and saliva was performed.
Subjects underwent a 40-hour constant routine (CR) protocol: enforced posture, dim light, hourly isocaloric meals, and sleep deprivation to minimize indirect effects.

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Last Updated: May 25, 2026

Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures

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Published on: November 11, 2016

In Vitro Bioluminescence Assay to Characterize Circadian Rhythm in Mammary Epithelial Cells

In Vitro Bioluminescence Assay to Characterize Circadian Rhythm in Mammary Epithelial Cells

Published on: September 28, 2017

Human Circadian Phenotyping and Diurnal Performance Testing in the Real World

Human Circadian Phenotyping and Diurnal Performance Testing in the Real World

Published on: April 7, 2020

Main Results:

Approximately 15% of identified metabolites in plasma and saliva exhibited circadian control under constant conditions.
Circadian regulation was particularly notable for plasma fatty acids and saliva amino acids.
These findings indicate a direct influence of the endogenous circadian clock on human metabolic pathways.

Conclusions:

The endogenous circadian clock directly impacts human metabolism independently of sleep-wake or feeding cycles.
Specific metabolites, including fatty acids and amino acids, are robust markers of circadian phase.
The study identifies potential small-molecule biomarkers for assessing human circadian phase and sleep pressure.