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Circadian urinary excretion rhythms in adrenalectomized rats
The American Journal of Physiology
|September 1, 1986
Summary
Adrenalectomy in rats altered urinary rhythms, but corticosterone administration influenced their timing. These findings suggest adrenal glands are not essential for urinary rhythms but regulate their phase.
Area of Science:
- Chronobiology
- Endocrinology
- Physiology
Background:
- Urinary rhythms are crucial physiological processes.
- The adrenal system's role in regulating these rhythms is not fully understood.
Purpose of the Study:
- To investigate the impact of the adrenal system on urinary rhythms in adrenalectomized (ADX) rats.
- To determine the influence of corticosterone on the phase setting of excretory rhythms.
Main Methods:
- Adrenalectomized (ADX) rats were studied under different light-dark cycles and constant light conditions.
- Corticosterone administration timing was manipulated to assess phase shifts.
- Phase-response curves were constructed for excretory rhythms.
Main Results:
- ADX rats showed shifted acrophases compared to controls under a light-dark cycle.
- ADX rats exhibited free-running rhythms under constant light.
- Corticosterone administration induced delay or advance shifts in urinary rhythms, allowing for phase-response curve construction.
Conclusions:
- The adrenal system is not essential for establishing urinary rhythms.
- Corticosterone plays a significant role in modulating the phase of urinary rhythms.
- The primary site of action for corticosterone is likely the central pacemaker, with potential secondary effects on renal oscillators.
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