Estrogen changes daily gene activity differently in brain and body clocks and in reproductive versus non-reproductive tissues of female rats

Chronic treatment with 17beta-estradiol (E2) altered the expression of clock-related genes in ovariectomized rats.

• E2 treatment advanced the peak of Per2 gene expression in the brain's suprachiasmatic nucleus.
• E2 did not affect the rhythm of Per2 or Per1 gene expression in the cerebral cortex.
• In nonreproductive tissues such as the liver and kidney, E2 delayed the phase and increased the amplitude of Per1 gene expression.
• Biphasic rhythms in Per1 and Per2 gene expression were observed in the uterus after E2 treatment.
• The effects of estrogen on gene expression differ between central and peripheral clocks in the brain, as well as between reproductive and nonreproductive tissues.

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