Editors' ChoiceCircadian Rhythms

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Science's STKE  03 Oct 2000:
Vol. 2000, Issue 52, pp. tw5
DOI: 10.1126/stke.2000.52.tw5

The daily rhythms of our bodies, and those of other mammals, are thought to be coordinated by a "master" clock located in the hypothalamus of the brain, which in turn controls peripheral "slave" clocks in the other organs. Balsalobre et al. identify glucocorticoid hormones as one of the signals that the master clock may use to coordinate the slaves. A synthetic glucocorticoid, dexamethasone, can transiently alter the phase of the rhythms in liver, kidney, and heart, at any time of day or night. However, the master clock in the brain, which contains no glucocorticoid receptor and so is not affected by dexamethasone treatment, responds to entraining signals only at certain times in its cycle.

Balsalobre, A., Brown, S.A., Marcacci, L., Tronche, F., Kellendonk, C., Reichardt, H.M., Schütz, G., and Schibler, U. (2000) Resetting of circadian time in peripheral tissues by glucocorticoid signaling. Science 289: 2344-2347. [Abstract] [Full Text]

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