Estrogen differentially regulates expression of Per1 and Per2 genes between central and peripheral clocks and between reproductive and nonreproductive tissues in female rats

• Published in: Journal of neuroscience research Vol. 82; no. 5; pp. 622 - 630
• Main Authors: Nakamura, Takahiro J., Moriya, Takahiro, Inoue, Shin, Shimazoe, Takao, Watanabe, Shigenori, Ebihara, Shizufumi, Shinohara, Kazuyuki
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.12.2005
• Subjects: Animals; Biological Clocks - drug effects; Biological Clocks - physiology; Cell Cycle Proteins; Cerebral Cortex - drug effects; Cerebral Cortex - metabolism; circadian rhythm; Circadian Rhythm - drug effects; Circadian Rhythm - physiology; clock gene; estrogen; Estrogens - metabolism; Estrogens - pharmacology; Estrous Cycle - drug effects; Estrous Cycle - physiology; Female; Gene Expression Regulation - drug effects; Gene Expression Regulation - physiology; Kidney - drug effects; Kidney - metabolism; Liver - drug effects; Liver - metabolism; Nuclear Proteins - genetics; Period; Period Circadian Proteins; Rats; Rats, Wistar; RNA, Messenger - drug effects; RNA, Messenger - metabolism; suprachiasmatic nucleus; Suprachiasmatic Nucleus - drug effects; Suprachiasmatic Nucleus - metabolism; Transcription Factors - genetics; Uterus - drug effects; Uterus - metabolism
• ISSN: 0360-4012; 1097-4547
• DOI: 10.1002/jnr.20677

Although it has long been established that estrogen alters circadian rhythms in behavior, physiology, and reproductive functions in mammals, the molecular mechanism for these effects remains unknown. To explore the possibility that estrogen affects circadian rhythms by changing the expression of clock‐related genes, we investigated the effects of chronic treatment with 17β‐estradiol (E2) on the expression of Per1 and Per2 genes in the brain (suprachiasmatic nucleus and cerebral cortex) and periphery (liver, kidney, and uterus) of ovariectomized rats by means of in situ hybridization and northern blotting. In the brain, E2 treatment advanced the peak of Per2 mRNA expression in the SCN; however, it failed to affect the rhythm of Per2 mRNA expression in the CX and Per1 mRNA expression in both the SCN and the CX. In nonreproductive peripheral tissues (liver and kidney), E2 delayed the phase and increased the amplitude of Per1 mRNA expression. In the reproductive tissues (uterus), biphasic rhythms in Per1 and Per2 mRNA were observed after E2 treatment. These findings suggest that the effects of estrogen are different between central and peripheral clock in the brain, and between reproductive and nonreproductive tissues in the periphery. © 2005 Wiley‐Liss, Inc.