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About 8-hour variation of circulating human endothelin-1
M Herold1, G Cornélissen, A Loeckinger
1Universitäts-Klinik für Innere Medizin, Innsbruck, Austria.
Peptides
|July 15, 1998
Summary
Cortisol exhibits a clear circadian rhythm, peaking in the morning. However, plasma endothelin-1 (ET-1) shows a significant 8-hour component, not a typical circadian rhythm, in healthy adults.
Area of Science:
- Endocrinology
- Chronobiology
- Cardiovascular Physiology
Background:
- Circadian rhythms regulate numerous physiological processes, including hormone secretion.
- Endothelin-1 (ET-1) is a potent vasoconstrictor with potential roles in cardiovascular regulation.
- Cortisol is a well-established hormone with a pronounced circadian rhythm.
Purpose of the Study:
- To investigate and compare the temporal patterns of plasma endothelin-1 (ET-1) and cortisol.
- To determine if ET-1 exhibits a circadian rhythm similar to cortisol in healthy individuals.
Main Methods:
- Hourly blood sampling over 24 hours in 7 healthy young adults.
- Measurement of plasma ET-1 and cortisol concentrations.
- Statistical analysis to identify circadian (24-hour) and other rhythmic components.
Main Results:
- Cortisol demonstrated a statistically significant circadian rhythm in all subjects and the group, with morning peaks.
- Plasma ET-1 did not show a statistically significant circadian rhythm in the group or most individuals.
- A significant approximately 8-hour rhythm component was identified for ET-1, distinct from cortisol's pattern.
Conclusions:
- Cortisol secretion follows a robust circadian pattern in healthy adults.
- Plasma ET-1 levels in healthy adults are not characterized by a typical 24-hour circadian rhythm.
- ET-1 exhibits a shorter, non-circadian rhythmic variation, suggesting different regulatory mechanisms compared to cortisol.
