Female 21-day-old rats injected subcutaneously with PMSG (30 IU/rat), followed by hCG (20 IU/rat) 48 h later, were sacrificed at the indicated times. The ovaries were removed, and total RNA was isolated. Rat GRP78 mRNA (A), rno-miR-144 (B), rno-miR-376a (C), and rno-miR-451 (D) expression levels were measured using real-time RT-PCR as described in the Materials and Methods. The amount of rat GRP78 mRNA, rno-miR-144, rno-miR-376a, and rno-miR-451 in the hCG 0 h group was set at 1. Data were normalized to 18S rRNA (for GRP78 mRNA) and 4.5S RNA(H) (for rno-miR-144, rno-miR-376a, and rno-miR451) levels in each sample and represent the mean ±SE of three independent experiments. *, significantly different from the control value at hCG 0 h, P<0.05.