Fig. 1

The number of CL, serum progesterone and 3β-HSD expression were increased 48 h to peak levels of progesterone production after PMSG/hCG injection. a Schematic diagram of ovary tissue selected 16, 24, 48, 72, and 96 h after PMSG/hCG injection. CL tissues were carefully collected from the ovaries after ovulation. b Luteal phase samples were collected at different time points based on CL morphology. c Serum progesterone levels were determined by progesterone ELISA kit (ALPCO) for 4–5 animals at each time point of the luteal phase during the estrous cycle. d Western blotting analysis of 3β-HSD, a marker of progesterone synthesis in the CL. The 3β-HSD level was normalized to that of the β-actin control. The histogram represents values of densitometry analysis obtained using the Image J software (NIH). The data are representative of at least three independent experiments conducted in triplicate. Values represent means ± SEM (4–5 mice/group) * P < 0.05, **P < 0.01, and ***P < 0.001