Fig. 2

ER-stress-induced reduction in progesterone production at the functional stage of CL is recovered by ROS scavenger NAC. a Schematic diagram showing the injection and collection times of the ER stress-regulator and ROS scavenger injection. Tm (an ER stress inducer; 0.5 μg/g body weight), TUDCA, (an ER stress inhibitor; 0.5 μg/g body weight), or NAC (a ROS scavenger; 1.0 μg/g body weight) were injected into mice 45 h after the PMSG/hCG injection. b Peak production of serum progesterone was measured (48 h after the PMSG/hCG injection) in the luteal phase. c Protein level of the UPR signaling activation marker CHOP in selected CL tissues was measured by western blot analysis after ER stress regulator and ROS scavenger stimulation. The levels of 3β-HSD, P450scc, and CHOP were normalized to that of β-actin. The histogram represents values of densitometry analysis obtained using the Image J software (NIH). The bar graphs represent the least-squares means ± SEM (4–5 mice/group) of three independent experiments. * P < 0.05, ** P < 0.01, and *** P < 0.001; Dunnett’s multiple comparison test compared to 48 h after PMSG/hCG injection