The Rev-erb alpha gene is regarded as a circadian clock gene and clock-regulated gene which regulates the circadian transcriptional/translational loop in a subtle way. Here, we first detected the circadian oscillation in mature granulosa cells from antral follicles using a real-time monitoring system of Per2 promoter activity with the addition of FSH. Then we used GSK4112, an agonist ligand of Rev-erb alpha, to investigate the function of Rev-erb alpha. GSK4112 treatment significantly reduced the Per2-dLuc amplitude and induced the Per2 oscillation phase advance shift. GSK4112 significantly inhibited Bmal1 mRNA expression, whereas it did clearly stimulate expression of StAR mRNA in a dose-dependent manner. Our data are the first to show the Rev-erb alpha function in the steroid biosynthesis of rat granulosa cells, and to suggest that Rev-erb alpha may coordinate circadian rhythm and metabolism in rat ovaries. (C) 2012 Elsevier Inc. All rights reserved.