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Continuous Free Cortisol Profiles-Circadian Rhythms in Healthy Men
R C Bhake1,2, V Kluckner3, H Stassen3
1University Hospitals Leicester National Health Service Trust, Leicester, United Kingdom.
The Journal of Clinical Endocrinology and Metabolism
|July 30, 2019
Summary
This study monitored subcutaneous free cortisol in healthy men for up to 72 hours, revealing consistent circadian rhythms despite daily activities. This research enables long-term ambulatory monitoring of cortisol profiles.
Area of Science:
- Endocrinology
- Chronobiology
- Physiology
Background:
- The pituitary-adrenal axis is a key model for circadian rhythms.
- Portable microdialysis devices allow for continuous monitoring of free cortisol in free-living individuals.
Purpose of the Study:
- To evaluate free cortisol profiles using microdialysis in individuals conducting daily activities.
- To assess the consistency of circadian cortisol rhythms over extended periods.
Main Methods:
- Healthy male volunteers participated in two experiments.
- Subcutaneous (SC) free cortisol was measured at 10-minute intervals for 24 hours and at 20-minute intervals for 72 hours using microdialysis.
Main Results:
- Circadian rhythms were observed in both serum total and SC free cortisol, with peaks around waking and troughs during sleep.
- SC free cortisol rhythms remained consistent over 72 hours in free-living individuals.
- Cortisol levels increased after lunch and were lowest after lights off.
Conclusions:
- This study is the first to report up to three consecutive 24-hour measurements of SC free cortisol in healthy individuals.
- The findings pave the way for ambulatory monitoring of free cortisol profiles for up to 72 hours.
- This monitoring is valuable for studying diseases involving the hypothalamic-pituitary-adrenal axis.
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