How the daily clock protein Per1 controls the endothelin system differently across tissues and times

Reduced Per1 expression significantly decreases ET-1 levels in the lung of Per1 heterozygous mice.

• The regulation of endothelin axis gene expression is tissue-specific and varies with circadian rhythms.
• In the renal inner medulla and liver, ETA and ETB mRNAs peak at opposite times of day.
• ET-1, ETA, and ETB expressions in the lung remain constant throughout the day, with a marked decrease in Per1 heterozygous mice.
• In the heart, ET-1 and ETA show time-dependent expression, while ETB does not.
• These findings suggest that the timing of endothelin receptor antagonist administration may be important.

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