Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Subscribe

Sci. Signal., 2 October 2012
Vol. 5, Issue 244, p. pt4
[DOI: 10.1126/scisignal.2003333]

PRESENTATIONS

Circadian Rhythms of Glucocorticoid Hormone Actions in Target Tissues: Potential Clinical Implications

Tomoshige Kino*

Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, MD 20892, USA.

A Presentation from the European Society for Paediatric Endocrinology (ESPE) New Inroads to Child Health (NICHe) Conference on Stress Response and Child Health in Heraklion, Crete, Greece, 18 to 20 May 2012.

Abstract: Organisms face unforeseen short- and long-term changes in the environment (stressors). To defend against these changes, organisms have developed a stress system that includes the hypothalamic-pituitary-adrenal (HPA) axis, which employs glucocorticoids and the glucocorticoid receptor (GR) for signal transduction. In addition, organisms live under the strong influence of day-night cycles and, hence, have also developed a highly conserved circadian clock system for adjusting their activities to recurring environmental changes. This regulatory system creates and maintains internal circadian rhythmicity by employing a self-oscillating molecular pacemaker composed of the Clock-Bmal1 heterodimer and other transcription factors. The circadian clock consists of a central master clock in the suprachiasmatic nucleus of the brain hypothalamus and peripheral slave clocks in virtually all organs and tissues. The HPA axis and the circadian clock system communicate with each other at multiple levels. The central clock controls the HPA axis, creating the diurnal oscillation of circulating adrenocorticotropic hormone and cortisol, and the HPA axis adjusts the circadian rhythmicity of the peripheral clocks in response to various stressors through the GR. Further, Clock-Bmal1 regulates the response to glucocorticoids in peripheral tissues through acetylation of the GR, possibly antagonizing the biologic actions of diurnally fluctuating circulating cortisol. Importantly, dysregulation in the clock system and the HPA axis may cause similar pathologic manifestations—including obesity, metabolic syndrome, and cardiovascular disease—by uncoupling circulating cortisol concentrations from tissue sensitivity to glucocorticoids.

* Presenter and corresponding author. E-mail: kinot{at}mail.nih.gov

Citation: T. Kino, Circadian Rhythms of Glucocorticoid Hormone Actions in Target Tissues: Potential Clinical Implications. Sci. Signal. 5, pt4 (2012).

Read the Full Text



To Advertise     Find Products


Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882