RESUMO
Circadian rhythm, which is internally generated by cell autonomous biological clocks, has been greatly concerned in recent years. This circadian system in mammals is composed of a master pacemaker in the suprachiasmatic nucleus (SCN) of the hypothalamus and slave clocks in most peripheral cell types. The clock genes and their coding proteins compose the feed-back loops of the circadian system. Light and food are two major Zeitgebers to synchronize circadian clocks. Light can induce clock genes expression and glucocorticoids release in the adrenal gland, while glucocorticoids can slow down the food-induced phase-shifting of peripheral circadian oscillators, suggesting that a close relationships may exist between glucocorticoids and the circadian gene expression. This article briefly reviews the recent progress in the interactions between them and suggests the direction of future researches.